consulting case study calculation

Case interview maths (formulas, practice problems, and tips)

Today we’re going to give you everything you need in order to breeze through maths calculations during your case interviews. 

Becoming confident with maths skills is THE first step that we recommend to candidates like Karthik , who got an offer from McKinsey. 

And one of the first things you’ll need to know are the 6 core maths formulas that are used extensively in case interviews. 

Let’s dive in!

• Case interview maths formulas
• Must-know formulas
• Optional formulas
• Cheat sheet
• Practice questions
• Case maths apps and tools
• Tips and tricks
• Practice with experts

Click here to practise 1-on-1 with MBB ex-interviewers

1. case interview maths formulas, 1.1. must-know maths formulas.

Here’s a summarised list of the most important maths formulas that you should really master for your case interviews:

If you want to take a moment to learn more about these topics, you can read our in-depth article about  finance concepts for case interviews .

1.2. Optional maths formulas

In addition to the above, you may also want to learn the formulas below. 

Having an in-depth understanding of the business terms below and their corresponding formulas is NOT required to get offers at McKinsey, BCG, Bain and other firms. But having a rough idea of what they are can be handy.

EBITDA = Earnings Before Interest Tax Depreciation and Amortisation

EBIDTA is essentially profits with interest, taxes, depreciation and amortisation added back to it.

It's useful for comparing companies across industries as it takes out the accounting effects of debt and taxes which vary widely between, say, Meta (little to no debt) and ExxonMobil (tons of debt to finance infrastructure projects). More  here .

NPV = Net Present Value

NPV tells you the current value of one or more future cashflows. 

For example, if you have the option to receive one of the two following options, then you could use NPV to choose the more profitable option:

• Option 1 : receive $100 in 1 year and $100 in 2 years
• Option 2 : receive $175 in 1 year

If we assume that the interest rate is 5% then option 1 turns out to be slightly better. You can learn more about the formula and how it works  here .

Return on equity = Profits / Shareholder equity

Return on equity (ROE) is a measure of financial performance similar to ROI. ROI is usually used for standalone projects while ROE is used for companies. More  here .

Return on assets = Profits / Total assets

Return on assets (ROA) is an alternative measure to ROE and a good indicator of how profitable a company is compared to its total assets. More  here .

1.3 Case interview maths cheat sheet

If you’d like to get a free PDF cheat sheet that summarises the most important formulas and tips from this case interview maths guide, just click on the link below.

Download free pdf case interview maths cheat sheet

2. Case interview maths practice questions

If you’d like some examples of case interview maths questions, then this is the section for you!

Doing maths calculations is typically just one step in a broader case, and so the most realistic practice is to solve problems within the context of a full case.

So, below we’ve compiled a set of maths questions that come directly from  case interview examples  published by McKinsey and Bain. 

We recommend that you try solving each problem yourself before looking at the solution. 

Now here’s the first question!

2.1 Payback period - McKinsey case example

This is a paraphrased version of question 3 on  McKinsey’s Beautify practice case :

How long will it take for your client to make back its original investment, given the following data?

• After the investment, you’ll get 10% incremental revenue
• You’ll have to invest €50m in IT, €25m in training, €50m in remodeling, and €25m in inventory
• Annual costs after the initial investment will be €10m 
• The client’s annual revenues are €1.3b

Note: take a moment to try solving this problem yourself, then you can get the answer under  question 3 on McKinsey’s website . 

2.2 Cost reduction - McKinsey case example

This is a paraphrased version of question 2 on  McKinsey’s Diconsa practice case :

How much money in total would families in rural Mexico save per year if they could pick up benefits payments from Diconsa stores?

• Pick up currently costs 50 pesos per month for each family
• If pick up were available at Diconsa stores, the cost would be reduced by 30%
• Assume that the population of Mexico is 100m 
• 20% of Mexico’s population is in rural areas, and half of these people receive benefits
• Assume that all families in Mexico have 4 members

Note: take a moment to try solving this problem yourself, then you can get the answer under  question 2 on McKinsey’s website . 

2.3 Product launch - McKinsey case maths example

This is a paraphrased version of question 2 on  McKinsey’s Electro-Light practice case :

What share of the total electrolyte drink market would the client need in order to break even on their new Electro-Light drink product?

• The target price for Electro-Light is $2 for each 16 oz (1/8th gallon) bottle
• Electro-Light would require $40m in fixed costs
• Each bottle of Electro-Light costs $1.90 to produce and deliver
• The electrolyte drink market makes up 5% of the US sports-drink market
• The US sports-drink market sells 8b gallons of beverages per year

2.4 Pricing strategy - McKinsey case maths example

This is a paraphrased version of question 3 on  McKinsey’s Talbot Trucks practice case :

What is the highest price Talbot Trucks can charge for their new electric truck, such that the total cost of ownership is equal to diesel trucks? 

• Assume the total cost of ownership for all trucks consists of these 5 components: driver, depreciation, fuel, maintenance, other. 
• A driver costs €3k/month for diesel and electric trucks
• Diesel trucks and electric trucks have a lifetime of 4 years, and a €0 residual value
• Diesel trucks use 30 liters of diesel per 100km, and diesel fuel costs €1/liter
• Electric trucks use 100kWh of energy per 100km, and energy costs €0.15/kWh
• Annual maintenance is €5k for diesel trucks and €3k for electric trucks
• Other costs (e.g. insurance, taxes, and tolls) is €10k for diesel trucks and €5k for electric trucks
• Diesel trucks cost €100k

2.5 Inclusive hiring - McKinsey case maths example

This is a paraphrased version of question 3 on  McKinsey’s  Shops Corporation practice case :

How many female managers should be hired next year to reach the goal of 40% women executives in 10 years? 

• There are 300 executives now, and that number will be the same in 10 years
• 25% of the executives are currently women
• The career levels at the company (from junior to senior) are as follows: professional, manager, director, executive
• In the next 5 years, ⅔ of the managers that are hired will become directors. And in years 6-10, ⅓ of those directors will become executives. 
• Assume 50% of the hired managers will leave the company
• Assume that everything else in the company’s pipeline stays the same after hiring the new managers

2.6 Breakeven point - Bain case maths example

This is a paraphrased version of the calculation portion of  Bain’s Coffee Shop Co. practice case : 

How many cups of coffee does a newly opened coffee shop need to sell in the first year in order to break even?

• The price of coffee will be £3/cup
• Each cup of coffee costs £1/cup to produce 
• It will cost £245,610 to open the coffee shop
• It will cost £163,740/year to run the coffee shop

Note: take a moment to try solving this problem yourself, then you can get the answer  on Bain’s website .

2.7 Driving revenue - Bain case maths example

This is a paraphrased version of the calculation part of  Bain’s FashionCo practice case : 

Which option (A or B) will drive the most revenue this year?

Option A: Rewards program

• There are 10m total customers
• The avg. annual spend per person is $100 before any sale (assume sales are evenly distributed throughout the year)
• Customers will pay a $50 one-time activation fee to join the program
• 25% of customers will join the rewards program this year
• Customers who join the rewards program always get 20% off

Option B: Intermittent sales

• For 3 months of the year, all products are discounted by 20%
• During the 3 months of discounts, purchases will increase by 100%

3. Case maths apps and tools

In the case maths problems in the previous section, there were essentially 2 broad steps: 

• Set up the equation
• Perform the calculations

After learning the formulas earlier in this guide, you should be able to manage the first step. But performing the mental maths calculations will probably take some more practice. 

Mental maths is a muscle. But for most of us, it’s a muscle you haven’t exercised since high school. As a result, your  case interview preparation  should include some maths training.

If you don't remember how to calculate basic additions, substractions, divisions and multiplications without a calculator, that's what you should focus on first.

In addition, Khan Academy has also put together some helpful resources. Here are the ones we recommend if you need an in-depth arithmetic refresher:

• Additions and subtractions
• Multiplications and divisions
• Percentages

Scientific notation

Once you're feeling comfortable with the basics you'll need to regularly exercise your mental maths muscle in order to become as fast and accurate as possible.

• Preplounge's maths tool . This web tool is very helpful to practice additions, subtractions, multiplications, divisions and percentages. You can both sharpen your precise and estimation maths with it.
• Victor Cheng's maths tool . This tool is similar to the Preplounge one, but the user experience is less smooth in our opinion.
• Mental math cards challenge app  (iOS). This mobile app lets you work on your mental maths easily on your phone. Don't let the old school graphics deter you from using it. The app itself is actually very good.
• Mental math games  (Android). If you're an Android user this one is a good substitute to the mental math cards challenge one on iOS.

4. Case interview maths tips and tricks

4.1. calculators are not allowed in case interviews.

If you weren’t aware of this rule already, then you’ll need to know this: 

Calculators are not allowed in case interviews. This applies to both in-person and virtual case interviews. And that’s why it’s crucial for candidates to practice doing mental maths quickly and accurately before attending a case interview. 

And unfortunately, doing calculations without a calculator can be really slow if you use standard long divisions and multiplications. 

But there are some tricks and techniques that you can use to simplify calculations and make them easier and faster to solve in your head. That’s what we’re going to cover in the rest of this section. 

Let’s begin with rounding numbers.

4.2. Round numbers for speed and accuracy

The next 5 subsections all cover tips that will help you do mental calculations faster. Here’s an overview of each of these tips: 

And the first one that we’ll cover here is rounding numbers. 

The tricky thing about rounding numbers is that if you round them too much you risk:

• Distorting the final result
• Or your interviewer telling you to round the numbers less

Rounding numbers is more of an art than a science, but in our experience, the following two tips tend to work well:

• We usually recommend that you avoid rounding numbers by more than +/- 10%. This is a rough rule of thumb but gives good results based on conversations with past candidates.
• You also need to alternate between rounding up and rounding down so the effects cancel out. For instance, if you're calculating A x B, we would recommend rounding A UP, and rounding B DOWN so the rounding balances out.

Note that you won't always be able to round numbers. In addition, even after you round numbers the calculations could still be difficult. So let's go through a few other tips that can help in these situations.

4.3. Abbreviate large numbers

Large numbers are difficult to deal with because of all the 0s. To be faster you need to use notations that enable you to get rid of these annoying 0s. We recommend you use labels and the scientific notation if you aren't already doing so.

Labels (k, m, b)

Use labels for thousand (k), million (m), and billion (b). You'll write numbers faster and it will force you to simplify calculations. Let's use 20,000 x 6,000,000 as an example.

• No labels: 20,000 x 6,000,000 = ... ???
• Labels: 20k x 6m = 120k x m = 120b

This approach also works for divisions. Let's try 480,000,000,000 divided by 240,000,000.

• No labels: 480,000,000,000 / 240,000,000 = ... ???
• Labels: 480b / 240m = 480k / 240 = 2k

When you can't use labels, the scientific notation is a good alternative. If you're not sure what this is, you're really missing out. But fortunately, Khan Academy has put together a good primer on that topic  here .

• Multiplication example: 600 x 500 = 6 x 5 x 102 X 102 = 30 x 104 = 300,000 = 300k
• Division example: (720,000 / 1,200) / 30 = (72 / (12 x 3)) x (104 / (102 x 10)) = (72 / 36) x (10) = 20

When you're comfortable with labels and the scientific notation you can even start mixing them:

• Mixed notation example: 200k x 600k = 2 x 6 x 104 x m = 2 x 6 x 10 x b = 120b

4.4. Use factoring to make calculations simpler

To be fast at maths, you need to avoid writing down long divisions and multiplications because they take a LOT of time. In our experience, doing multiple easy calculations is faster and leads to less errors than doing one big long calculation.

A great way to achieve this is to factor and expand expressions to create simpler calculations. If you're not sure what the basics of factoring and expanding are, you can use Khan Academy again  here  and  here . Let's start with factoring.

Simple numbers: 5, 15, 25, 50, 75, etc.

In case interviews some numbers come up very frequently, and it's useful to know shortcuts to handle them. Here are some of these numbers: 5, 15, 25, 50, 75, etc. 

These numbers are common, but not particularly easy to handle.

For instance, consider 36 x 25. It's not obvious what the result is. And a lot of people would need to write down the multiplication on paper to find the answer. However there's a MUCH faster way based on the fact that 25 = 100 / 4. Here's the fast way to get to the answer:

• 36 x 25 = (36 / 4) x 100 = 9 x 100 = 900

Here's another example: 68 x 25. Again, the answer is not immediately obvious. Unless you use the shortcut we just talked about; divide by 4 first and then multiply by 100:

• 68 x 25 = (68 / 4) x 100 = 17 x 100 = 1,700

Factoring works both for multiplications and divisions. When dividing by 25, you just need to divide by 100 first, and then multiply by 4. In many situations this will save you wasting time on a long division. Here are a couple of examples:

• 2,600 / 25 = (2,600 / 100) x 4 = 26 x 4 = 104
• 1,625 / 25 = (1,625 / 100) x 4 = 16.25 x 4 = 65

The great thing about this factoring approach is that you can actually use it for other numbers than 25. Here is a list to get you started:

• 2.5 = 10 / 4
• 7.5 = 10 x 3 / 4
• 15 = 10 x 3 / 2
• 25 = 100 / 4
• 50 = 100 / 2
• 75 = 100 x 3 / 4

Once you're comfortable using this approach you can also mix it with the scientific notation on numbers such as 0.75, 0.5, 0.25, etc.

Factoring the numerator / denominator

For divisions, if there are no simple numbers (e.g. 5, 25, 50, etc.), the next best thing you can do is to try to factor the numerator and / or denominator to simplify the calculations. Here are a few examples:

• Factoring the numerator: 300 / 4 = 3 x 100 / 4 = 3 x 25 = 75
• Factoring the denominator: 432 / 12 = (432 / 4) / 3 = 108 / 3 = 36
• Looking for common factors: 90 / 42 = 6 x 15 / 6 x 7 = 15 / 7

4.5. Expand numbers to make calculations easier

Another easy way to avoid writing down long divisions and multiplications is to expand calculations into simple expressions.

Expanding with additions

Expanding with additions is intuitive to most people. The idea is to break down one of the terms into two simpler numbers (e.g. 5; 10; 25; etc.) so the calculations become easier. Here are a couple of examples:

• Multiplication: 68 x 35 = 68 x (10 + 25) = 680 + 68 x 100 / 4 = 680 + 1,700 = 2,380
• Division: 705 / 15 = (600 + 105) / 15 = (15 x 40) / 15 + 105 / 15 = 40 + 7 = 47

Notice that when expanding 35 we've carefully chosen to expand to 25 so that we could use the helpful tip we learned in the factoring section. You should keep that in mind when expanding expressions.

Expanding with subtractions

Expanding with subtractions is less intuitive to most people. But it's actually extremely effective, especially if one of the terms you are dealing with ends with a high digit like 7, 8 or 9. Here are a couple of examples:

• Multiplication: 68 x 35 = (70 - 2) x 35 = 70 x 35 - 70 = 70 x 100 / 4 + 700 - 70 = 1,750 + 630 = 2,380
• Division: 570 / 30 = (600 - 30) / 30 = 20 - 1= 19

4.6. Simplify growth rate calculations

You will also often have to deal with growth rates in case interviews. These can lead to extremely time-consuming calculations, so it's important that you learn how to deal with them efficiently.

Multiply growth rates together

Let's imagine your client's revenue is $100m. You estimate it will grow by 20% next year and 10% the year after that. In that situation, the revenues in two years will be equal to:

• Revenue in two years = $100m x (1 + 20%) x (1 + 10%) = $100m x 1.2 x 1.1 = $100m x (1.2 + 0.12) = $100m x 1.32 = $132m

Growing at 20% for one year followed by 10% for another year therefore corresponds to growing by 32% overall.

To find the compound growth you simply need to multiply them together and subtract one: (1.1 x 1.2) - 1= 1.32 - 1 = 0.32 = 32%. This is the quickest way to calculate compound growth rates precisely.

Note that this approach also works perfectly with negative growth rates. Let's imagine for instance that sales grow by 20% next year, and then decrease by 20% the following year. Here's the corresponding compound growth rate:

• Compound growth rate = (1.2 x 0.8) - 1 = 0.96 - 1 = -0.04 = -4%

See how growing by 20% and then shrinking by 20% is not equal to flat growth (0%). This is an important result to keep in mind.

Estimate compound growth rates

Multiplying growth rates is a really efficient approach when calculating compound growth over a short period of time (e.g. 2 or 3 years).

But let's imagine you want to calculate the effect of 7% growth over five years. The precise calculation you would need to do is:

• Precise growth rate: 1.07 x 1.07 x 1.07 x 1.07 x 1.07 - 1 = ... ???

Doing this calculation would take a lot of time. Fortunately, there's a useful estimation method you can use. You can approximate the compound growth using the following formula:

• Estimate growth rate = Growth rate x Number of years

In our example:

• Estimate growth rate: 7% x 5 years = 35%

In reality if you do the precise calculation (1.075 - 1) you will find that the actual growth rate is 40%. The estimation method therefore gives a result that's actually quite close. In case interviews your interviewer will always be happy with you taking that shortcut as doing the precise calculation takes too much time.

4.7. Memorise key statistics

In addition to the tricks and shortcuts we’ve just covered, it can also help to memorise some common statistics. 

For example, it would be good to know the population of the city and country where your target office is located. 

In general, this type of data is useful to know, but it's particularly important when you face  market sizing questions . 

So, to help you learn (or refresh on) some important numbers, here is a short summary:

Of course this is not a comprehensive set of numbers, so you may need to tailor it to your own location or situation.   

5. Practice with experts

Sitting down and working through the maths formulas we've gone through in this article is a key part of your case interview preparation. But it isn’t enough.

At some point you’ll want to practise making calculations under interview conditions.

You can try to do this with friends or family. However, if you really want the best possible preparation for your case interview, you'll also want to work with ex-consultants who have experience running interviews at McKinsey, Bain, BCG, etc.

If you know anyone who fits that description, fantastic! But for most of us, it's tough to find the right connections to make this happen. And it might also be difficult to practice multiple hours with that person unless you know them really well.

Here's the good news. We've already made the connections for you. We’ve created a coaching service where you can do mock interviews 1-on-1 with ex-interviewers from MBB firms. Learn more and start scheduling sessions today.

Consulting & Case Interview Math Practice Guide

The truth is you do not need to be an expert mathematician to work as a consultant, still, you will need to do a lot of calculations when working in this field. 

The math concepts utilized in consulting are not more challenging than those studied from academic math. More exactly, it is different and attempting to solve problems the same way as in school will not be effective. 

This article will explain to you what makes math so important for aspiring consultants and provide you with some crucial math areas in which you need to be proficient in as well as how to best practice consulting math.

Table of Contents

Do you need math in consulting or case interviews?

Math is omnipresent in case interviews….

This industry is known for its complex business problems and challenging strategic decisions, which require a strong foundation in mathematics. Thus, mathematics is a fundamental skill that is essential for success in consulting case interviews .  

Consulting companies usually use case interviews to test candidates' quantitative skills and problem-solving abilities, which means that proficiency in math is a must-have skill for any aspiring consultant.

Candidates who are proficient in math have a significant advantage in the case interview process. They are better equipped to analyze data, create models, and make informed decisions based on quantitative analysis . This is because math skills enable candidates to think logically and analytically, which is crucial in the consulting industry.

In addition to helping candidates solve complex business problems, good math skills can also help them to solve the case more efficiently. By quickly identifying the key data points and using mathematical formulas to analyze them, interviewees can save time and leave more time for insightful ideas and recommendations.

… because it’s always there in real consulting work

Additionally to case interviews, the consulting industry as a whole also places a high value on mathematical ability. Without a strong foundation in math, consultants may struggle to work effectively in their daily duty.

Math skills are essential for performing data analysis and modeling, which are crucial aspects of the consulting job. Consulting firms rely heavily on data-driven insights to deliver value to clients, and math skills are necessary to analyze data, identify patterns, and draw meaningful conclusions that can help clients make informed decisions.

Secondly, to develop engaging talks and reports that successfully illustrate information and suggestions, solid arithmetic skills are also required. 

These abilities are essential since clients rely on consultants to provide them with actionable insights that can drive their business forward. By using mathematical formulas and models, consultants can present complex data in a clear and concise manner , making it easier for clients to understand and act upon.

Furthermore, math skills are crucial for financial analysis, which is another critical aspect of the consulting job. Consultants must be able to analyze financial data, create financial models, and make informed decisions based on quantitative analysis . This requires a strong foundation in math, including knowledge of statistics, probability, and financial mathematics.

7 Types of math you need in consulting

Basic operations (add, subtract, multiply, divide)

Definition: Basic math refers to the fundamental arithmetic operations used in mathematics. It includes addition (+), subtraction (-), multiplication (x), and division (/), which are used to perform simple calculations and solve basic math problems.

These fundamental arithmetic operations are used in various calculations and are necessary for understanding more advanced math concepts. Basic math is used to calculate various metrics, ratios, and other complex work in consulting as well as case interviews. Without a strong foundation in basic math, it would be challenging to perform such calculations accurately and efficiently.

Suppose a consulting project requires calculating the total cost of producing 10,000 units of a product. The cost per unit is $50 for direct materials, $30 for direct labor, and $20 for overhead expenses. To calculate the total cost, we need to use addition and multiplication:

Total cost = (Direct materials cost per unit + Direct labor cost per unit + Overhead cost per unit) x Number of units

Total cost = ($50 + $30 + $20) x 10,000 = $1,000,000

Ratios and percentages

Definition: Ratio is a comparison of two or more quantities, while percentage is a ratio expressed as a fraction of 100. Ratios and percentages are used to express relationships between different variables and are commonly used in finance, statistics, and other fields.

Consultants frequently use ratios and percentages to analyze financial statements, assess market share, and evaluate operational performance. Additionally, they evaluate various scenarios and spot shifts over time using this kind of calculation.

Suppose a consulting project requires analyzing the profitability of a company. We need to calculate the gross profit margin, which is the ratio of gross profit to revenue expressed as a percentage. If the gross profit is $500,000 and the revenue is $1,000,000, we can calculate the gross profit margin as follows:

Gross profit margin = (Gross profit / Revenue) x 100%

Gross profit margin = ($500,000 / $1,000,000) x 100% = 50%

Management accounting formulas and principles

Definition: Accounting math is a set of mathematical principles and methods used in accounting to record, classify, and analyze financial data. It includes the calculation of various financial ratios, such as profit margin, return on investment, and debt-to-equity ratio, which are used to evaluate a company's financial health.

Accounting math involves the use of specific formulas and calculations to prepare financial statements, such as balance sheets, income statements, and cash flow statements. Consultants regularly have to use accounting math to interpret financial data, identify areas for improvement, and develop financial models.

Common accounting math formulas:

Balance Sheet Equation: Assets = Liabilities + Equity

Income Statement Equation: Revenue - Expenses = Net Income

Gross Margin Ratio = (Revenue - Cost of Goods Sold) / Revenue

Debt-to-Equity Ratio = Total Debt / Total Equity

Current Ratio = Current Assets / Current Liabilities

Suppose a consulting project requires analyzing the financial statements of a company. We need to calculate the current ratio, which is a measure of the company's liquidity. If the current assets are $1,000,000 and the current liabilities are $500,000, we can calculate the current ratio as follows:

Current ratio = Current assets / Current liabilities

Current ratio = $1,000,000 / $500,000 = 2

Basic finance formulas and principles

Definition: Finance math refers to the mathematical principles and methods used in finance to analyze and manage financial data. It includes the calculation of financial ratios, such as return on investment, net present value, and internal rate of return, which are used to evaluate investment opportunities and make financial decisions.

Finance math includes advanced financial modeling and analysis techniques, such as discounted cash flow analysis, net present value calculations, and internal rate of return analysis. Consultants will need to use finance math with purposes like evaluate investment opportunities, assess risk, and make strategic recommendations.

Present Value (PV) = Future Value / (1+interest rate)^number of period

Future Value (FV) = Present Value x (1+interest rate)^number of period

Net Present Value (NPV) = sum of all present values of cash inflows - sum of all present values of cash outflows

Internal Rate of Return (IRR) = the interest rate at which the NPV of an investment is zero

Return on Investment (ROI) = (Gain from Investment - Cost of Investment) / Cost of Investment

Suppose a consulting project requires evaluating investment opportunities. We need to calculate the net present value (NPV) of an investment, which is the difference between the present value of cash inflows and the present value of cash outflows. If the cash inflows for the first year are $50,000 and the cash inflows for the second year are $100,000, and the discount rate is 10%, we can calculate the NPV as follows:

NPV = Cash inflow year 1 / (1 + Discount rate)^1 + Cash inflow year 2 / (1 + Discount rate)^2

NPV = $50,000 / (1 + 10%)^1 + $100,000 / (1 + 10%)^2 = $126,456.83

Basic statistics and probabilities

Definition: Probability is the branch of mathematics that deals with the study of random events and their likelihood of occurring. It involves calculating the probability of different outcomes based on the available information and using this information to make predictions.

Probability is used in consulting to assess the likelihood of different outcomes and events, and to develop risk management strategies. Consultants use probability to analyze market trends, identify potential risks, make forecasts, and develop contingency plans.

Suppose a consulting project requires analyzing customer data to identify patterns. We need to calculate the probability of a customer making a purchase given that they have visited the company's website. If the number of website visitors is 10,000 and the number of customers who made a purchase is 500, we can calculate the probability as follows:

Probability of purchase given website visit = Number of customers who made a purchase / Number of website visitors

Probability of purchase given website visit = 500 / 10,000 = 5%

“Weighted” calculations

Definition: This is a method of calculating a value based on the weights assigned to different variables. It is commonly used in finance and economics to determine the overall performance of a portfolio, and in other fields to calculate averages of different sets of data.

A weighted average is used to calculate the average of a set of numbers, with each number being multiplied by a corresponding weight. This type of math is very useful for consultants since it helps them to analyze financial data, such as revenue growth or customer satisfaction, and to develop performance metrics.

Suppose a consulting project requires analyzing survey data. We need to calculate the overall satisfaction score for a product, which is based on ratings for different features. If the ratings for feature A, B, and C are 3, 4, and 5 respectively, and the weights for these features are 30%, 40%, and 30% respectively, we can calculate the overall satisfaction score as follows:

Overall satisfaction score = Rating for feature A x Weight for feature A + Rating for feature B x Weight for feature B + Rating for feature C x Weight for feature C

Overall satisfaction score = 3 x 0.3 + 4 x 0.4 + 5 x 0.3 = 3.0

Exhibits (chart, tables, diagrams)

Definition: An exhibit is a graphical representation (chart) of data that is used to present information in a clear and easily understandable format. It can be used to display trends, patterns, and relationships between different variables, making it a useful tool for visualizing complex data sets.

Consultants need to use charts and graphs to present complex data and analysis in a clear and concise manner. They use various types of charts, such as pie charts, bar charts, and line graphs, to convey important information to clients and stakeholders. They also help consultants to identify trends and patterns in data, making it easier to draw meaningful conclusions and make informed suggestions.

This part of mathematics is quite diversified since there are numerous types of charts, tables, and diagrams, thus I cannot provide examples for every situation. You can watch the video reference below to learn more about Exhibits in consulting.

Consulting mental math

Why is mental math in consulting important.

This may also be categorized as a type of mathematics, but I've decided to address it separately to emphasize the significance it is. In the consulting industry, quick math is essential. Although the resulting numbers don't have to be 100% accurate (usually the error margin will be around 5%) , you will have to give a quick result.

In many circumstances, there is not a sufficient amount of time to get out a calculator, indeed, they are not even permitted in tests and case interviews . Hence, Mental math is a crucial component of an interview that frequently gets noticed by interviewers when it helps candidates to solve the questions and show their mental agility. 

When you have become a consultant, mental calculation is even more important since it not only helps us save a ton of time but also builds credibility with people around . You wouldn't want to look sluggish and perplexed in front of your managers, clients or interviewers, would you?

How to do mental math for consulting?

For our Comprehensive Math Drills, we have developed a methodical approach to mental calculations with large numbers, consisting of two main steps: ESTIMATION and ADJUSTMENT. This method is used for multiplication, division, and percentage.

Step 1 - Estimation

• Simplify the large numbers by  taking out the zeroes (e.g. 6,700,000 becomes 6.7 and 000000)
• Round the resulting 1-to-2-digit numbers for easier calculations (e.g.: 6.7 becomes 7)

Step 2 - Adjustment

• Perform simple calculations with the multiplicands
• Adjust in the opposite direction of the previous rounding and put the zeroes back in

Step 3 - Percentages

• To do percentages , multiply the original number with the numerator then divide by 100.

Detail example:

• Multiplication: 1,234 x 5,678

Take out zeroes: 12.34 x 56.78 | 00 00

Round: 12 x 60 | 00 00

Calculate: 720 | 0 000

Adjust and add zeros: 7,200,000 (equal down-rounding and up-rounding roughly cancels each other out)

Accurate result: 7,006,652 | Error margin: 2.7%

• Division 8,509 / 45

Take out zeroes: 85 / 4.5 | 00 / 0

Round: 90 / 4.5 | 00 / 0

Calculate: 20 | 0

Adjust and add zeros: 190 (up-rounding means downward adjustment)

Accurate result: 189.09 | Error margin: 0.48%

• Percentage 70% of 15,940

Convert %: 0.7 x 15,940

Take out zeroes: 7 x 15.9 | One 0 in, three 0 out

Rounding: 7 x 16 | One 0 in, three 0 out

Calculate: 112 | One 0 in, three 0 out

Add zeros: 11,200

Adjust : 11,150 (up-rounding means downward adjustment)

Accurate result: 11,158 | Error margin: 0.07%

For percentage calculations, it is even easier with the “ Zeroes management ” . We know that the final answer will have roughly the same number of digits as the original 15,940, something like 1x,xxx or x,xxx. So when having 112 after step “Calculate”, we know the final answer would be close to 11,200.

Mental Math Tips:

• Write down numbers : it’s always a good idea to have a visual of the numbers themselves on paper. This makes it 100 times easier,  especially with “zeroes management” work.
• Sanity check: always take a very brief moment to ask yourself “is this result logical?”; if 70% of 15,940 equals 111,500, perhaps something is wrong with your “zeroes management”. Sometimes you can compare the outcome with another obvious data
• Shortcut percentages: convert percentages into easy, common calculations (e.g.: 33%, 25%, 20% into /3, /4, /5…) if possible. In fact, know as many of these shortcuts as you can.
• It is better to be long than to be wrong: If your mental math is not good and cannot calculate quickly, do not hesitate to ask for a little more time to get the most accurate answer.

Consulting math practice

Step 1: learn about yourself.

The first step to acing consulting math is to understand yourself, your strengths, your weaknesses and your needs. Assess your current skill level and identify areas where you need to improve . This can be done by reviewing your previous academic performance, past work experiences, and feedback from others.

One of the best ways to learn more about the consulting industry and the type of math skills required is to network with those who have experience in this field. They can provide valuable advice and insights on what to expect during tests/interviews and which math skills are most important. 

This is an extremely important step, but it might be challenging to carry out since many people do not know/have contact with any consultants, former consultants and interviewers. If there are a few people in your network, that's fantastic; if not, you can use our Coaching services to get the most reliable information from current consultants.

Step 2: Developing an actionable plan 

Once you have a clear understanding of yourself, you now need to establish a clear, actionable strategy to improve your consulting math skills . This plan should include a list of resources and activities that will help you promote self-study and focus on the areas that need the most improvement.

There are many resources available for consulting math practice , including online courses, textbooks, and practice mental exercise. You may also want to consider hiring a tutor or attending a community to receive personalized guidance and feedback.

When developing your plan, it is important to set realistic goals and establish a timeline for achieving them. This will help you stay motivated and track your progress along the way.

Step 3: Implement the plan

Now that you have a plan in place, it's time to implement it. Set aside dedicated time each day or week to practice your consulting math skills . Consistency is key, so make sure you stick to your schedule and do not skip any practice sessions.

When practicing, it is important to focus on understanding the underlying concepts rather than simply memorizing formulas and equations. Work through practice problems step-by-step and identify where you might be making mistakes. 

Moreover, reviewing your work and seeking feedback from others can help you improve your approach and increase your accuracy.

Step 4: Adjust the plan to best suit your capacity

Finally, It is crucial to modify your strategy as necessary to accommodate your capabilities. If you find that you are struggling with a particular concept or area, don't be afraid to pivot and adjust your plan accordingly. Consider seeking additional resources or seeking guidance from others who have experience.

At the same time, do NOT get too caught up in perfecting every aspect of consulting math is also matter. Recognize your strengths and weaknesses and focus on improving in areas where you can make the most progress. 

Remember that the goal is not to be perfect but to demonstrate your ability to approach and solve complex problems in a logical and efficient manner.

Common math mistakes in consulting 

Messing up formulas.

The inability to apply the formula errors or mess up with numbers/signs is a common mistake made by candidates. Anyone may make this error because of both internal factors like mathematical confusion and external factors like time pressure.

To avoid this issue, you must first be cautious throughout the procedure, go step-by-step, and carefully examine the data and signs . If you need extra time, kindly request it, keep in mind that the important thing is getting the proper outcome.  

Secondly, practice using different formulas to solve various problems before the interview. Ensure that you have a clear understanding of when and how to apply each formula.

Excess or missing zeroes

Another common math mistake is losing units in calculations. When performing calculations, you must keep track of units to ensure that your answer is meaningful and relevant to the context of the problem. Losing units can make your answer meaningless and confusing, which could lead to wrong conclusions.

In order to avoid making this error, it's essential to label each step of your calculation and remember to carry the units as you work with them . Keeping your calculations well-organized will prevent you from losing track of the units. 

Another tip is try to reduce the unit of each metric as much as possible by assigning it to a term. For example, you can write “42,000,000” to “42M”. This will both ease your calculations and avoid confusion, but remember to add the units back to the final result 

Missing the bigger picture

The math done during a consulting case interview serves as a tool, not an end in and of itself. It is crucial to remember that calculations are part of a more significant business problem that you have to solve . 

Many candidates get wrapped up in calculations, arrive at the correct final number, but forget why they were doing the math and the real purpose of the number they have just found out.

To prevent this mistake, remember the significance of the figures you are calculating in the context of your particular business case. One tactic to use is to write the question asked at the top of your sheet before deep diving into your math. 

As you go through your calculation and as you prepare to present your solution, keep reminding yourself the question you were originally asked and ask yourself if the result you got from your calculation is actually answering it. Then when you explain your answer, do so in a way that clearly shows you understand what your final number means.

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Case interview math (mental math) tools, formulas and tips.

Case Interview Math (Mental Math) Tools, Formulas and Tips

Consulting case interview mental math practice is a must as part of one’s overall consulting case interview preparation. All management consulting firms, and certainly McKinsey, BCG and Bain, expect candidates to be very comfortable with quantitative data, statistics, and the ability to make decisions and client recommendations based on data.

Management consultants at firms like McKinsey, BCG, Bain, Deloitte spend a lot of time working with numbers, charts, calculations, financial models in excel and other math work, often mental math work. So any consulting case interview mental math test, and there are really multiple mental math tests scattered throughout the consulting case interview process is something you have to be well prepared for.

This does not mean that you need to have a math degree to have the right level of consulting case interview mental math skills. But you do need to know what is expected of you and you do need to practice mental math a lot.

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How is consulting case interview mental math different from academic math?

Because management consulting is all about solving difficult problems, usually under extreme pressure, the case interviewer is expecting a candidate to approach math problems in a specific way. In academic settings the most important element of solving math problems is accuracy. Accuracy is also very important for case interview math but management consultants usually work under extreme time pressure. And so answers are often required to be close enough to guide towards the “right” recommendation, versus being 100% accurate.

For example, imagine you are asked to calculate the market size for baby diapers for sensitive skin in Singapore. If this was a problem within an academic setting you would be expected to give an accurate answer correct to the decimal point. In consulting case interview settings you will have to make many educated estimations to arrive at, hopefully, a close enough answer. And then you will be expected to do what we call a sanity check to ensure that your answer actually makes sense.

Let’s take a look at an example from a real McKinsey engagement, mentioned by one of our trainers, Kevin P. Coyne. In case you don’t know, Kevin is a former McKinsey worldwide strategy practice co-leader and he leads The Consulting Offer II , which you can access if you join our Premium membership or FIRMSconsulting Insider level.

In this example, Kevin mentioned serving a large bank and during initial interviews with employees of the bank, Kevin’s team noticed that 100% of the profit for that bank was coming from one business unit. That does not mean that all other business units were operating at a loss. But combined all other business units of that bank had zero profit. So the bank was dependent on this one unit to generate all their profits.

Kevin’s team further uncovered that a lot of clients that the unit served were really old. To give a more accurate answer on how bad the situation was Kevin’s team selected only 1 letter in the alphabet and studied the age of all the clients whose name started from that letter, let’s say it was letter B.

This exercise uncovered that within the next 5 years that bank would lose something like half of its clients. And it does not mean the bank will have those clients for 5 years and then they will disappear. No, the clients will start dying now and within 5 years the client base will be about half smaller than now.

And younger people were not interested in that type of service. Doing the same analyses for all clients within the unit would be cost-prohibitive and will take significantly longer, and the limited analysis conducted was more than enough to understand that the bank was in serious trouble and drastic action was required.

This is a great example of how math in real consulting settings is often focused on getting close enough/good enough answers fast and cheap. And as a great management consultant, you will need to have strong enough business judgment to know what is good enough and what is required and to never waste the client’s money and other resources on unnecessary analyses.

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A comprehensive estimation cases guide, what do you mean by case interview math.

Strengthening your mental math and written math skills is one of the most important elements of preparing for case interviews.

As part of a case interview process, your mental and written math skills will be tested in multiple ways. If you are strong in academic math you are in a good place. However, the style of math used during case interviews is quite different vs. math problems in the academic context, as we discussed above, and takes time to get comfortable with.

Some examples of what case interview math test can include:

Case interview math test can include word problems . Word problems used as part of case interviews are similar to the type of word-based problems you practiced for as part of your GMAT preparation or preparation for other standardized tests. And such a case interview math test may or may not include a business-based context.

Case interview math can be tested during a full case . In fact, full cases almost always test math along with other skills. For example, coming back to the example above, you may be asked to estimate the market size for diapers for sensitive skin babies in Singapore as part of a full case of your client considering entering the Singapore market. As part of the case, you may also be asked to work with many graphs and charts, which we refer to as data cases . We cover data cases extensively in The Consulting Offer , our flagship program where we help real candidates prepare for interviews with McKinsey, BCG, Bain, Deloitte, etc. You can track candidates’ preparation at various stages, all the way from networking, editing resume and preparing for standardized tests to getting an offer and deciding if they should accept an offer. You can track Ritika joining McKinsey Chicago, Jen joining Bain Boston, Assel joining McKinsey Europe after 5 years out of the workforce and with no prior work at MBB (never before been done), Sanjeev joining BCG, Alice joining McKinsey NYC and much more.

Mental math is also tested as part of case interview math tests. In fact, it is tested a lot as part of the case interview process. You will be required to do math in your head and very fast. This is often one of the most difficult components of a case interview for candidates. The Consulting Offer will help you prepare.

Standard math such as multiplication, division, fractions, percentages, and other concepts are routinely tested. Case interview math tests are usually baked into a case and math is just a component to finding a solution within a specific business context.

In all examples of case interview math above, speed and relative accuracy matter. And the use of calculators is not allowed. So it is crucial to practice and be ready to handle case interview math tests fast, accurately, and without a calculator.

Consulting case interview math formulas

Revenue  = Volume x Price

Cost  = Fixed cost + Variable cost

Profit  = Revenue – Cost

Profit margin / Profitability  = Profit / Revenue

Return on Investment (ROI)  = Annual profit / Initial investment

Breakeven / Payback Period  = Initial investment / Annual profit

EBITDA  = Earnings Before Interest Tax Depreciation and Amortization. EBIDTA is essentially profits with interest, taxes, depreciation and amortization added back to it. It’s useful when comparing companies across various industries.

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Bonus download, proven strategies for effective leadership and results, fast mental math: rounding numbers.

What will help you become faster in doing mental math during consulting case interviews is rounding numbers. For example, ~82 million population of Germany becomes 80 million, ~46.7 million population becomes 45 million. The key to rounding numbers is to round them carefully, in a way that does not distort too much the final answer. A good guideline to follow is not to round by more than 10%. It is also helpful to round both up and down as you are working through the case, so the effects, to some degree, cancel each other out. At the end also make sure you check if your answer actually makes sense.

Fast mental math: dealing with large numbers

The key to dealing with large numbers, like 200 million, for example, is to remove zeros and then add them back later. Use labels (m,k,b) to help you keep track. So if you have 200 million, it becomes 200 m to help you remember that it is millions. 200,000 will be 200k. 10 billion will become 10 b. The key to achieving fast mental case interview math is to simplify. For example, 5 x 30 million becomes 5 x 3 = 15 with 7 zeros.

Fast mental math: break down numbers into smaller parts

When dealing with case interview math, another trick that will help you work through the problem faster is breaking down numbers into smaller parts. For example, 14 x 6 = (10 x 6) + (4 x 6) = 84.

Fast mental math: subtracting from numbers with 1 followed by zeros

This is another trick for faster case interview math. Again, simplify. 1000-536 becomes 999-536+1 = 464.

Fast mental math: group numbers into multiple of 10 (addition)

Another trick for fast case interview math is to group numbers into multiple of 10 (for addition). 3+7 + 4 + 6 +13 +7 +21 becomes 10 + 10 + 20 + 21 = 61.

Other tips to achieve fast case interview math (mostly mental math) during a consulting case interview

Here are a few tips to keep in mind to help you perform better during a consulting case interview when it comes to case interview math (and mostly mental math).

• At the beginning of the case ask your interviewer if it is ok to round numbers. Most of the time they will say yes and it will make math calculations much easier and faster.
• Do not rush. If you make a mistake it will take you even longer to fix it. This is if you even catch your mistake. You may also catch your mistake by the time when the interviewer will not give you an opportunity to fix it. And case interview math mistakes can be very embarrassing and lead to a completely wrong recommendation. Of course, there is a lot of time pressure during consulting case interviews so do not take any longer than you need. You need to find a good balance. This comes with a lot of practice. We provide a lot of opportunities for you to practice case interview math. Some full cases are provided below and you will find more on our YouTube channel. And, of course, you can unlock access to all candidates and seasons of The Consulting Offer when you become Premium member (more details below).
• Do not be afraid to write things down when you feel you need it.
• Keep your writing organized. Let say you are estimating how many cars will be purchased in Germany in 2020. As you are putting down numbers for each element of your equation keep it neat and organized so you don’t get confused and it will also help you avoid silly mistakes.
• Do not state your answer to an interviewer as a question. Be confident in your answer.
• As part of your preparation refresh key math topics like ratios, fractions, percentages, averages, and probability.  Khan Academy  is a great place to refresh your math skills. And you will have more than enough opportunities to practice fast mental case interview math as you go through various candidates and seasons within The Consulting Offer (part of  Premium membership).

Practice consulting case interview math / mental math with full cases

As you work through the cases remember to focus on all elements of good case performance, not just math. People usually underestimate how important other elements of case interview preparation are, including FIT. And only realize after being rejected that the elements they ignored during preparation were the reason for the rejection. Learn from the mistakes of others. Take all elements of case interview preparation seriously.

BUSINESS CASE EXAMPLE #1: MCKINSEY, BAIN, BCG ACQUISITION CASE

This case is a McKinsey style case, of medium level difficulty. It should take you 15-20 minutes to solve this case.

The question is given upfront, at 2:02. The part in black is the part the interviewer would share with you and a part in grey is the part interviewer may share as the case progresses. The interviewer wants to see if the interviewee understands the case and asks the right questions.

The case question is quite explicit but even so we will show you how you can adjust the case and make the case more explicit.

Everything rests on the key question. If anything is not part of the key question, ignore it. Even though lots of information is provided, take time to understand and set up the case.

Always show why information is needed, and show progress so the interviewer is they are willing to provide more information. It is a barter. And always use the case information provided and the appropriate language to push the case forward.

BUSINESS CASE EXAMPLE #2: COMPREHENSIVE MARKET ENTRY CASE

We did this recording a few months after we completed the training with Rafik (TCO I). This is one of the most complex market entry cases we had to put together. It has elements of operations, elements of pricing, elements of costing and, obviously, elements of market entry. And it is probably the most difficult market entry case we can do because most market entry cases that most interviewers focus on have a strong market attractiveness element, market profitability element. But very few people actually look at the operational issues of entering the market. And it does not matter who you are interviewing with: Bain, BCG or McKinsey. The bulk of the focus usually goes towards analyzing the market worthiness but not a lot on the operational issues. So we decided, in this case, to flip it around and give this case a strong operational theme.

BUSINESS CASE EXAMPLE #3: PEPSI’S LOS ANGELES BOTTLING PLANT

Operations cases can be tackled in two ways: strategy and operations and within operations from productivity and the supply chain side. This case uses the supply chain side.

This case is candidate-led. As we mentioned above, candidate-led cases are much harder than interviewer-led cases. That is why we at FIRMSconsutling place so much more emphasis on teaching you how to lead cases vs. relying on the interviewer to lead. This will be considered an operations case. Pay attention to a very insightful brainstorming at 14:50 which includes at least one idea you most likely would not come up with if you were solving this case before watching this video.

What else can I do to improve my case interview math?

Mental math is a muscle. But most of us do not exercise it enough once we leave school. So your case interview preparation needs to include math training.

First refresh your knowledge and ability to calculate basic multiplications, divisions, additions, and subtractions, without a calculator. The Consulting Offer program (a part of Premium membership) includes ongoing opportunities to practice this. We also have many cases available for free on the FIRMSconsulting YouTube channel to get you started.

And there are other tools you can use for case interview math prep.

Khan Academy has some resources that you may find helpful. Here are some helpful links:

• Percentages
• Scientific notation
• Additions and subtractions
• Multiplications and divisions

You will need to regularly practice to get comfortable with mental and written math. Case interview math tests require you to do all math calculations fast and accurately. We recommend working through a few sessions of The Consulting Offer a day to ensure multiple opportunities to practice math and other skills you need to give yourself the highest chance to get an offer from firms like McKinsey, BCG, Bain, Deloitte, etc.

Go through a few sessions every day and you will start feeling more comfortable over time not just with case interview math but with your resume, networking, estimations, brainstorming, answering FIT questions in a way that answers what the interviewer is REALLY asking you.

You will also develop or strengthen the ability to lead and handle difficult cases, and the ability to develop your own framework uniquely tailored to solve a particular case, and much more. View it as an investment in skills that will serve you for the rest of your life vs. just searching for tips and tricks to get an offer from McKinsey, BCG, Deloitte, et al.

Additionally, some candidates found the following tools helpful as supplemental materials along with The Consulting Offer. We have not tested those tools but are sharing them in case you would like to explore them.

Mental math games (Android). This one is similar to the mental math cards challenge app on iOS (below).

Mental math cards challenge app (iOS). This mobile app is a good choice if you are an iOS user.

Magoosh’s Mental Math Practice – Arithmetic Flashcards (iOS + Android). And here is another free math app that uses flashcards. And it allows you to track your progress as you study.

MConsultingPrep: math drills

Preplounge: mental-math (registration required)

Case Interview: calculations   (registration required)

How FIRMSconsulting can help me?

You will need to get comfortable doing calculations fast and accurately. And this comes with a lot of practice. If you will be using The Consulting Offer to prepare for your consulting case interviews you will have what seems to be never-ending opportunities to practice mental and written math as part of the full cases and as part of particular questions such as estimations, etc.

Management consulting jobs are very competitive, and working with FIRMSconsulting can mean the difference between getting an offer, or multiple offers, from your target firms and barely getting an offer from the company you hoped you never would need to settle for. And the latter example is something I, unfortunately, observed many of my MBA classmates settled for.

When it comes to case interview math The Consulting Offer program, all 5 seasons of it and counting, with various candidates, includes everything you need to master not just case interview math, but all key aspects of consulting case interviews.

Don’t miss out by investing your time with general math drills when you can practice real-world case interview math examples while being taught by former consulting partners.

If you want the most comprehensive guidance for consulting case interviews math, and other aspects of case interview preparation, so you go to your interviews confidently, become a Premium or FC Insider level member now. And if you still have questions contact FIRMSconsulting ( [email protected] ) to find out why candidates even from top schools like Harvard, Stanford, and MIT choose us when they need consulting case interview preparation help, and stay with us for years and years once they get coveted jobs at McKinsey, BCG, Bain, Deloitte, etc.

WHAT IS NEXT? If you have any questions about our membership training programs (StrategyTV.com/Apps & StrategyTraining.com/Apps) do not hesitate to reach out to us at support @ firmsconsulting.com. You can also get access to selected episodes from our membership programs when you sign-up for our newsletter above or here . Continue developing your  strategy skills .

Cheers, Kris

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Can you use a calculator in a case interview?

Math plays an important role in case interviews conducted by top consulting firms such as McKinsey , BCG , and Bain . These firms are looking for candidates who can quickly and accurately perform basic mathematical calculations under pressure.

The math used in a case interview is usually simple arithmetic, including basic addition, subtraction, multiplication, and division. Candidates may also be expected to perform calculations involving fractions, decimals, and percentages. In addition, some case interviews may require more advanced mathematical skills, such as calculating compound interest or determining the present value of an investment. The latter is especially relevant for specialized hires.

A common question I often receive and see on forums is if you are allowed to use a calculator in a case interview. In this article, I want to answer this and provide some tips on how to deal with case math calculations.

Why are consulting firms testing your math skills?

The use of math in a case interview is evaluated by top consulting firms because it provides insight into a candidate’s ability to think critically and solve problems. These firms are looking for candidates who can make quick, accurate calculations and use their mathematical skills to support their arguments and recommendations. The use of math also helps to assess a candidate’s ability to work under pressure and make decisions in real-time. By requiring candidates to perform mathematical calculations during a case interview, top consulting firms are able to get a better understanding of a candidate’s analytical skills, problem-solving abilities, and overall aptitude for consulting work.

Case Math Mastery Course and Drills

Approach case interview math like a real consultant with the most comprehensive preparation program on the market. Learn from our McKinsey interviewer experience and benefit from the detailed curriculum of the guidebook and the video program as well as 40 hours of practice.

You cannot use a calculator in a case interview

Now, can you bring your calculator to the interviews or use one during a Zoom interview? The short answer is no (and you should also not try to game the system by calculating outside of the webcam’s view).

Whether you have already learned that calculators are not allowed or not while preparing for a case interview, this can be a daunting experience for those who are used to relying on technology to help them perform basic mathematical calculations, which is actually everyone. 🙂 You have likely not done any mental math since early high school and since then relied on calculators and spreadsheet software such as Excel.

If you are using a calculator, consulting firms are not able to evaluate your performance and skill in this regard. While 99% of your quantitative work on the job is done using Excel, there might be situations where you need to demonstrate strong mental math skills, for instance, during a client meeting to make some quick estimations or to defend or challenge statements.

To be fully comprehensive, I once coached a candidate for a U.S. McKinsey office who was allowed to use a calculator during the interview. Out of more than 1350 sessions I have done at the time of writing with hundreds of clients, she was the only one across all MBBs, tier-2 firms, Big 4, in-house consulting, and boutique consulting firms that was allowed a calculator and she did not know either why she had that privilege (she got the offer btw).

For anyone else, there is likely no way around it and you should spend some time getting back to speed with mental calculations.

What should you do instead?

Luckily, there are simple tips and techniques that can help you improve your mental math skills and practice them regularly.

Simple tips for mental math

• Learn the basics. One of the most important things you can do to prepare for a case interview is to learn how to sum, subtract, multiply, and divide double-digit numbers quickly and accurately. Once you have remembered, for instance, how to perform divisions again, it’s time to simplify the process.
• Round numbers to simplify calculations. For example, instead of calculating 29 x 4, round 29 to 30 and multiply it by 4. The answer is 120, which is close to the actual answer of 116. If you are multiplying or summing numbers, try rounding one number up and the other one down to cancel out the effects. If you are dividing or subtracting, round both numbers in the same direction. Try to stay within a 5-10% margin.
• Break down problems into smaller parts. Instead of trying to solve a complex problem all at once, break it down into smaller, more manageable parts. For example, if you need to multiply 25 x 8, first multiply 25 x 2 (which is 50) and then multiply 50 x 4 (which is 200). Alternatively, you could also calculate 25 x 10 – 25 x 2 = 250 – 50 = 200.
• Learn how to deal with zeros . Working with zeros can be a challenge, especially when multiplying or dividing large numbers. One strategy for avoiding mistakes when working with zeros is to always use 10^power instead of zeros. For example, 200 x 8000 = 2 * 10^2 x 8 * 10^3 = 2 x 8 * 10^(2+3) = 16 * 10^5. This may look complicated at first, but with practice, it becomes much easier and helps you avoid losing zeros or making other errors.
• Practice with simple calculations before moving on to more complex ones. Start with simple problems and gradually increase the difficulty level as you become more comfortable with mental math. For instance, our case math course follows a logical sequence from simple calculations to intermediate and complex ones.
• Learn how to take clean and logical notes and keep track of your calculations. Write down everything including the input numbers, the calculation steps, intermediate results, and the final result when doing mental calculations. Find a system of note-taking that works for you. Your calculations will be more organized and if you make a mistake with a track record, you can quickly fix it and move on.

More advanced tips for mental math

• Use estimation to sanity-check answers. When you’re finished with a mental math problem, use estimation to see if your answer is reasonable. For example, if you calculate that 123 x 28 is 3,444, check to see if the answer is reasonable. Since 28 is close to 30 and 123 is close to 120, you can estimate that the answer should be around 3,600. You could also frontload this before actually going through the accurate calculation. In the best case, interviewers are already happy with the approximate result (see Rounding above)
• Learn mental math shortcuts. For instance, break calculations apart. For example, you can quickly calculate 12 x 15 by recognizing that 12 x 10 is 120 and 12 x 5 is 60, so the answer is 180.
• Memorize multiplication tables, squares, and cubes. For instance, memorize the division table up to x/20, such that you are able to quickly translate fractions (e.g., 6/7 = 86%). This will help you quickly calculate percentage problems without the need for a calculator. Memorize key numbers like powers of 2, 5, and 10, which can be helpful in solving problems.

Techniques for practicing mental math

• Practice mental math daily. Like any skill, practicing mental math regularly is crucial for improvement. Burn through drills using timers to create a more realistic scenario. Set yourself the goal to accurately complete a certain amount of calculations in a given timeframe.
• Use real-life situations to practice mental math . Try to incorporate mental math into everyday activities, like calculating the cost of groceries, determining the tip for a restaurant bill, or calculating the time and distance for a trip.
• Practice mental math with a partner or group. Practicing mental math with others can be fun and motivating. You can compete against each other or work together to solve problems.
• Track progress and celebrate small improvements. Keep track of your progress by setting goals and tracking your improvement over time. Celebrate small improvements to stay motivated. Create an error log to collect all the errors you have made. This will help you learn, prevent similar errors in the future, and guide your preparation (e.g., if you keep making the same mistakes in one area or type of calculation, it might be worthwhile to focus more on that area).

Remember, the key is to practice, practice, and practice again until you are confident in your abilities.

Use our free case interview math drill generator

Speaking of practice…

Boost your case interview preparation with our Case Interview Math Drill Generator. Seamlessly create tailored math problems designed to boost your speed and accuracy and stand out in the interview process field.

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Overcoming mental math challenges

If you struggle with mental math, you’re not alone. Math anxiety and working memory limitations are common challenges that many candidates face during case interviews and preparation. To overcome these challenges, try these tips:

• Take deep breaths and stay calm. When you feel anxious or overwhelmed, take deep breaths and focus on staying calm. Remember that mental math is a skill that can be improved with practice.
• Break down problems into smaller parts. If you’re struggling with a complex problem, break it down into smaller parts. This can help you stay focused and avoid feeling overwhelmed.
• Use mnemonic devices to remember key information. Mnemonic devices, like acronyms, can be helpful for remembering key numbers or formulas.

Seek help if you need it. If you’re struggling with mental math, don’t hesitate to seek help from a tutor or coach. They can provide personalized guidance and support to help you improve your skills.

In conclusion, the use of calculators is not allowed in case interviews for a reason. Among many other things, consulting firms want to test your basic mathematical skills and assess your ability to think on your feet in a stressful situation.

Remember to practice regularly, use real-life situations to practice, and track and celebrate small improvements along the way. With dedication and perseverance, you can become a mental math whiz in around four weeks. Case interview math is never too difficult yet requires a certain set of skills that need to be demonstrated under time pressure in a challenging environment.

Our Case Interview Math Academy

If you want to improve your case interview and problem-solving skills and learn the key habits and tricks that make you succeed in any McKinsey, BCG, and Bain interview, try our case practice . Many students that started their BCG careers, Bain careers, or McKinsey careers, went through our training.

We have created a program with detailed insider learning materials, 25 videos, and a guidebook as well as 2,000 practice drills that mimic the McKinsey, BCG, and Bain case interview math as well as the aptitude and analytics test math for you here:  Case Interview Math Mastery .

Case Interview Math Mastery (Video Course and 2,000 Exercises)

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Florian spent 5 years with McKinsey as a senior consultant. He is an experienced consulting interviewer and problem-solving coach, having interviewed 100s of candidates in real and mock interviews. He started StrategyCase.com with the goal to make top-tier consulting firms more accessible for top talent, using tailored and up-to-date know-how about their recruiting. He ranks as the most successful consulting case and fit interview coach, generating more than 450 offers with MBB, tier-2 firms, Big 4 consulting divisions, in-house consultancies, and boutique firms through direct coaching of his clients over the last 3 years. His books “The 1%: Conquer Your Consulting Case Interview” and “Consulting Career Secrets” are available via Amazon.

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S T R E E T OF W A L L S

Consulting case study 101: an introduction to frameworks.

Before we look at individual Cases, it is important to begin by looking at analysis frameworks that commonly can be used to address Case Study questions. In this chapter, we will outline some of the core frameworks and some additional Consulting concepts that are important to grasp and will form part of many interviews. The frameworks will be helpful to answer certain types of cases, depending on the type of case.  In reality, few case interviews or real-life business situations cover just one concept or business problem, so you have to have the flexibility to apply a range of concepts/structures.  For example, a Company bringing a new product to market would require a market size analysis, competitor analysis, as well as understanding the key customer segments.

The more you practice, the easier the cases will become and the more articulate and structured you’ll be in your answers.

An important note on this: historically, the vast majority of Consulting candidates have used specific business frameworks to answer cases.  Frameworks remain important as concepts to answer Case Studies, but you should absolutely avoid any rigid use of a specific framework . In reality, the main purpose of learning the frameworks is to help you to structure your answers , just as the case situations in our later examples should do.

The key frameworks that follow should be used directly in certain Case situations , but more broadly they should be used as a way to expand your strategic thinking , which is the critical component of success in the Case Study interview process. Ultimately, a top-flight candidate will build his or her own framework/structure for evaluating the Case as it progresses, often drawing from many of the frameworks and concepts in this module, and potentially others. In other words, you should absolutely avoid using the phrase, “I will apply framework X to this case.” However, be aware of the “famous” frameworks in case they are mentioned in an interview setting, and don’t be shy about referencing them as you dive into the specifics of the Case Study you’re evaluating.

Porter’s Five Forces

Porter’s Five Forces has become an incredibly well known framework in the business strategy world. It is probably the most famous of all of them. It was introduced by Harvard Professor and Monitor Consulting firm founder Michael Porter.  Porter’s Five Forces is a high-level framework that you can draw upon to perform a market landscape and competitor dynamics analysis. It can help determine whether a market or company is attractive, whether the client for whom the analysis is being performed is a private equity firm thinking about buying a company, or a major company thinking about entering or exiting a certain market segment. In most cases, a Case Study will address at least some of the components found in this framework.

Here are the Five Forces in detail:

Porter’s Five Forces

• Legal or regulatory barriers (for example, patents or government contracts)
• Economies of scale
• Cost advantage (for example, unique access to lower raw material costs)
• Access to distribution channels
• Product differentiation (for example, how is this product different?)
• Industry growth rate
• Industry fragmentation
• Level of switching costs
• Motivation to reduce prices (for example, from excess capacity)
• Level of substitute products
• Buyer’s decision influenced by supplier
• Supplier inputs/products have high switching costs
• Supplier has potential to forward integrate
• Supplier accounts for large share of the inputs/products
• High customer/client concentration
• Level of commoditization of product/input
• Level of switching costs for buyer
• Buyer has significant product/market information
• Substitute products/services that can compete on price and/or quality
• Switching costs to shift to substitute products

This simple framework has been around for a long time as a way to think about any industry or company, and applies broadly to a wide range of Case Study questions. If you compare the description below to that of Porter’s Five Forces above, you will see that there is substantial overlap.

The “3 Cs” approach is to address any Case situation by assessing the:

• Competitors
• Customers/clients

The 3 C’s

• Pros and cons of product/service
• Value chain
• Revenue (price × volume) and expenses
• Core competencies
• Regulatory environment
• Distribution network
• Management and core employees
• Market share
• Fragmentation
• Financial situation (for example, deep pocket competitors?)
• Other competencies (for example, marketing or distribution channels)
• Value proposition versus client
• Demographics (age, gender, etc.)
• Value of core customers/clients
• Wants and needs of customers/clients
• Customer/client segment sizes
• Customer/client segment shares
• Customer/client segment growth rate
• Product characteristics
• Personnel (especially for B2B)

This framework is often used specifically whenever there is a marketing component involved in a case (for example: how to increase sales resulting from any profitability optimization case, deciding on an approach to enter a market, etc.). When combined with the 3 Cs, this framework can cover many topics and as you practice more Case Study questions, you’ll develop a better sense of when and how to draw from these frameworks.

The “4 Ps” approach is to address a marketing-oriented Case situation by assessing the:

The 4 P’s

• Commoditized or differentiated?
• How close are the substitutes?
• Value proposition versus substitutes (price, quality, etc.)
• Switching costs
• Why are clients/customers purchasing the product?
• Brand, availability, service, value, reliability, aesthetic, etc.
• Is our product sufficiently better to justify a higher price? Or is it somewhat commoditized?
• Customer loyalty/lock-in
• Supply/demand: current state of demand and supply for the product or service
• Price of substitute products/services
• Price of competitor products/services
• Brand position and perception
• What is the cost for the client to produce the product or offer the service?
• Select/exclusive channels or wide distribution network?
• Seamless delivery to customers
• Internal transport or outsource?
• Specific areas of a site online
• Product placement in stores
• Customer/client awareness
• Is the Company reaching and attracting its target market?
• What are the most effective marketing campaign strategies?
• Return on marketing spend
• Are we retaining our customers/clients?
• Can we up-sell or cross-sell to our current customers/clients?

SWOT (Strengths, Weaknesses, Opportunities, Threats)

SWOT analysis is more of a mini-framework, specifically for quickly evaluating a single company in an industry. In that regard, it’s far less complete than other frameworks, and can often miss important details. However an interviewer could potentially ask you for a SWOT analysis, and you should be prepared to apply it in that case.

SWOT is effectively a quick, high-level market landscape/competitive dynamics analysis arranged using the following terminology:

SWOT Analysis

• Strengths: Company strengths within an industry
• Weaknesses: Company weaknesses within an industry
• Opportunities: Company opportunities available within the industry (or potentially by branching into a new industry)
• Threats: Company threats within the industry (or potentially from companies whose primary business is in another, related industry, or from disruptive technologies that potentially threaten all companies in an industry)

It should be noted that SWOT can be extended from comparing a specific company to the others in the industry, to comparing a specific industry or sub-industry to other, related industries or sub-industries within the economy. For example, a classic SWOT analysis might entail benchmarking Delta Airlines with the airline industry as a whole; an extension could entail benchmarking the entire airline industry against the broad transportation sector.

Other Frameworks

You should be very familiar with the well-known frameworks already discussed in this chapter, although it is unlikely that an interviewer would ask you to use a particular framework in your analysis. Instead, it is typically expected that you draw on the concepts encompassed by these frameworks and/or the concepts that we will outline in the next chapter, which breaks down the common Case Study interview question types .

In addition to these frameworks, there are a number of other frameworks that you will read about on certain Consulting firm sites, but you will probably not be expected to know them in detail or apply them specifically in an interview. It does not hurt, however, to be familiar with them. Therefore, we include these example frameworks for your reference and encourage you to at least familiarize yourself with the basics of them:

• The BCG Growth Share Matrix for evaluating product or business lines
• The McKinsey 7S Framework for evaluating organizational effectiveness
• The Product/Market Grid to determine growth opportunities
• Force Field Analysis for Change Management
• The Affinity Diagram for organizing ideas and information

Additional Analysis Concepts

There are additional, relatively simple analytical techniques that you should be prepared for in Consulting Case Study interviews. These techniques tend to be numerical, and occur frequently, although none are comprehensive or broad enough to fall into the category of a “Framework”:

Break-Even Analysis

Fixed vs. variable expenses, net profit margin, return on investment (roi), compound annual growth rate (cagr).

• Lifetime Customer Value (LCV; sometimes referred to as “User Lifetime Value”)

Product Life Cycle

Opportunity cost, elasticity (supply or demand).

• Financial Statements, Accounting, and Valuation

Let’s take a deeper look at each analysis category.

• The gist of Break-Even Analysis cases is that the Fixed Costs of a business—i.e., the costs that are unavoidable—need to be overcome by making profit from sales of products. Presumably, each incremental sale contributes to profit at a rate that can be determined (or at least estimated); the question that is to be answered is, “How many units do I have to sell in order to overcome my Fixed Costs, i.e., to ‘Break Even’?”
• In other words, the Break-Even Point is the number of units sold at which Revenue equals Total Expenses (Fixed Expenses plus Variable Expenses).
• Break-Even Analysis is often applied when deciding whether to develop a new product or make a capital equipment investment, as well as helping in making decisions around how to price products and service and the number of units to produce.
• Formulaically, Break-Even Number of Units = Fixed expenses ÷ (Revenue per unit – Variable Expenses per unit).
• Note that the expression ( Revenue per unit – Variable Expenses per unit ) is often referred to as the Unit Contribution Margin .
• An understanding of how to analyze Expenses and differentiate Fixed Expenses from Variable Expenses is useful in order to run a Break-Even Analysis of a company.
• Break-Even Analysis can get more complex, as there are microeconomic and macroeconomic considerations that can change both the Fixed and Variable Expenses, but the basic concept is an important one; therefore you will likely come across some form of Break-Even Analysis in Consulting Case Study interviews.
• Note that this concept can also be translated into a question on Break-Even Price , i.e., “Assuming a certain volume of sales, what is the sales price required in order to break even?”
• Formulaically, Break-Even Price = (Fixed Expenses ÷ Sales Volume) + Variable Expenses per unit .
• Note that the expression ( Fixed Expenses ÷ Sales Volume ) equates to the required Unit Contribution Margin at the assumed Sales Volume in order to break even. In other words, Break-Even Price = Required Unit Contribution Margin + Variable Expenses per Unit .
• Fixed Expenses (or Fixed Costs ) are expenses that do typically fluctuate regardless of the production or sales levels. These expenses can be viewed as “unavoidable,” at least in the short-term. Typical examples for Fixed Expenses include Rent, Insurance, Mortgage Payments, and Corporate Overhead Expenses.
• Variable Expenses (or Variable Costs ) are impacted by changes in production or sales levels – typical examples include are Raw Materials, Direct Labor Expenses (wages and benefits), and delivery costs.
• Understanding a Company’s Fixed vs. Variable Cost structure is important in a variety of cases (such as in Break-Even Analysis, discussed above).
• When analyzing a Case, always keep in mind that total Fixed Expenses remain constant as volume rises (or falls), but Fixed Expenses per unit decline as volume rises (rise as volume falls). For example, if a computer component manufacturer has $1,000 of Fixed Expenses and produces 100 components, then the $1,000 of Fixed Expenses will be spread across 100 components (= $10 of Fixed Expenses per unit). If the Company produced 200 components, then the Fixed Expenses per unit would decrease to $5 per unit.
• Variable Expenses, meanwhile, rise proportionately as volume increases, so Variable Expenses per unit remain constant.
• When an interviewer asks a candidate to calculate the Net Profit Margin (a.k.a. Profit Margin or Net Income Margin ), he or she will usually be referring to the total Net Income of a company or business line as a percentage of its Revenue: Net Profit Margin = Net Income ÷ Total Revenue.
• The interviewer could also refer to Gross Profit Margin , which is simply Gross Profit as a percentage of revenue: Gross Profit Margin = Gross Profit ÷ Total Revenue
• Similarly, the interview may also refer to Operating Profit Margin ( EBIT Margin ), or EBITDA Margin . In both cases, thus is simply the figure in question (Operating Profit, a.k.a. EBIT, or EBITDA) as a percentage of Revenue.
• Return on Investment (ROI) is a ratio that determines the return, or Profit, from capital invested. ROI is used in consulting interviews as a way to evaluate the return of a particular investment or to assess the feasibility of a potential investment or acquisition. Many companies have an internal ROI metric for capital investments.
• Standard ROI is calculated as follows: Profit from the Investment (Revenue minus Costs) ÷ Capital Invested .
• Note: Return on Assets (ROA) is a variation of this concept, but instead revolves around all capital invested in a project (Liabilities + Equity), rather than just Equity invested, which is typical for an ROI calculation.
• The Compound Annual Growth Rate (CAGR) is the percentage rate at which any figure, such as number of units sold, a population, or an investment must grow in each year to reach a given end value over a certain amount of time. (Note that this is not the only growth path to grow from a beginning number to an ending number, but it is the only growth path that is the same growth rate every year .)
• The formula to calculate CAGR is: [(Ending Value ÷ Beginning Value)^(1 ÷ Number of Years)] – 1.
• For example: If sales grew from $1,000 in the year 2001, when a store opened, to $2,100 in 2012, what is the CAGR?
• Answer: [(2,100 ÷ 1,000)^(1 ÷ 11)] – 1 = 2.1^(0.090909) = 7.0%
• Thus, the CAGR between 2001 and 2012 was 7.0%.
• CAGR is very similar in concept to Internal Rate of Return (IRR), which is the annual rate of return on an investment if its value grows by a specific multiple over a specific amount of time.
• Use the Rule of 72 to estimate CAGR whenever possible. The rule of 72 simply states that a quantity will roughly double in value whenever the number of years times the annual growth rate equals 72.
• Using the above example, we can see that the quantity slightly more than doubled, so the answer should be slightly above (72 ÷ 11) percent, or slightly above 6.6%. Indeed, it is!

Lifetime Customer Value (LCV)

• Lifetime Customer Value (LCV) projects the total profitability attributed to a firm’s future relationship to a typical customer.
• The idea behind this microeconomic analysis is to determine the reasonable cost to win or acquire a customer (or to maintain an existing customer, i.e., prevent him or her from “churning,” or switching to a competitor). It can also be used to determine level and type of customer service to provide, and as another way to estimate the value of a business. (In theory, the value of a business should equal the number of existing customers × the LCV per customer , plus growth opportunities.)
• The steps to calculate the LCV are as follows:
• Estimate the remaining customer years; in other words, how long is a typical customer expected to last with the company?
• Estimate future Revenue per year per customer, based on product volume per customer × price
• Estimate Total Expenses for producing those products (either separating Fixed Costs out or allocating them on a per-customer basis)
• Calculate the Net Present Value of the future profit (Revenue – Expenses) per customer (in other words, discount these future profits back into today’s equivalent dollars)
• Important for market sizing problems, the Product Life Cycle helps to calculate and project the annual market size for a given market/industry. It is often used by companies to project their own anticipated Revenue figures.
• Formulaically, Annual Market Size = Total Revenue of a product outstanding ÷ Average life of the product . For example, “Total Revenue of a product outstanding” might represent the sticker price of all cars driven in the US, while the “Average life of the product” would be the average number of years a car is driven.
• It is also worth knowing the four steps in the Product Life Cycle Curve , as the concept could come up in a hypothetical product case.
• Emerging: A new product or technology that is in initial adoption phases and therefore has very rapid growth rates (for example: electric cars)
• Growth: Product adoption is becoming widespread but still growing at an above-average rate (for example: smartphones)
• Maturity: Product adoption is widespread, or at least stabilized; growth typically comes only from price increases and growth in GDP (for example: breakfast cereal)
• Declining: Technological obsolescence, shifting consumption patterns, or increased market competition has resulted in total growth rates that are below-average or negative (for example: dairy products or wireline telephones)
• Opportunity Cost simply refers to the concept that if a person or company does X , the person or company necessarily cannot also do Y .  This is an important concept throughout business and consumer decision making, as there are only finite resources available in most cases (time, money, etc.).
• Thus, for example, it is unwise for a company to invest $1 million in a project earning $3 million if that same investment prevents it from investing the $1 million in another opportunity that would earn $10 million. In this case, the Opportunity Cost can be defined as the loss of incremental profit of $7 million ($10 million potential profit lost minus the $3 million earned).
• If X does not prevent also doing Y , then there is said to be “no Opportunity Cost” of doing X with respect to Y . In the above example, if the company had $2 million to invest and the capacity to manage both projects, it could reap the profits from both projects, i.e., $13 million.
• Elasticity is a concept from microeconomics that describes the tradeoff between Quantity and Price.
• Specifically, Elasticity is the ratio of a percentage change in quantity to the percentage change in price. Formulaically, Elasticity = % Change in Quantity Demanded or Supplied ÷ % Change in Price .
• For example, if an increase in the price of oranges from $1.00 apiece to $1.50 apiece causes demand for those oranges to fall from 100 units to 80 units, then the % Change in Quantity = –20% and the % Change in Price = 50%. Therefore the Elasticity of Demand = (–20 ÷ 50) = –0.4.
• Note that for normal goods, Elasticity of Demand will always be negative (higher prices mean less quantity is purchased) while Elasticity of Supply will always be positive (higher prices mean that suppliers are willing to produce and/or supply more goods).
• The concept comes up in multiple types of cases, such as pricing optimization. Clients often ask what the impact would be on volume if they adjust the price. Usually the correct answer is to increase prices in Inelastic markets (price increases lead to a relatively small decrease in products sold) and decrease them in Highly Elastic markets (price increases lead to a large decrease in product sold).

Financial Statements, Accounting and Valuation

Unlike Investment Banking interviews, which can be detailed and highly technical in terms of Finance and Accounting, Consulting interviews and the Consulting job itself revolve much more around estimation and exercising business judgment and “what-if” analysis. Rarely would a Consultant be called upon to develop and maintain a detailed, precise financial model for Discounted Cash Flow valuation, for example.

That being said, a basic-to-moderate understanding of the Income Statement, Balance Sheet and Statement of Cash Flows, and how they work together, is very relevant to many interviews. (You might even be provided with a basic Income Statement or Balance Sheet of a company as part of a Case Study interview question.)

Rather than reinventing the wheel and writing content on Finance and Accounting in this guide, we recommend you review any standard, basic Financial Accounting textbook to familiarize yourself with the components of basic Financial Statements:

• Income Statement (Revenue, Expenses, and Profit)
• Balance Sheet (Assets, Liabilities, and Equity)
• Statement of Cash Flows (Cash Flows broken out into the following categories of sources: Operating Activities, Investing Activities and Financing Activities)

We also recommend that you familiarize yourself with some basic core Finance concepts (Net Income, EBIT (Operating Profit), EBITDA, Free Cash Flow, Internal Rate of Return, Net Present Value, and Enterprise Value are good places to start) and core Valuation techniques (Cost of Capital, Comparable Company Analysis, Precedent Transaction Analysis, Discounted Cash Flow analysis, and Leverage Buyout analysis).  Although these concepts will not be tested and do not form a major part of general Consulting Case Study interviews, these topics can appear in a general discussion about a particular business situation and you should be able to discuss them at least on a basic level.

If you are applying for a job in Business Development, or for a Consulting position in a Corporate Finance group or at a firm that does a lot of Corporate Finance Consulting work, then you should definitely study up and be prepared for these core Finance and Accounting concepts, because they will likely be tested on in detail in your interviews. In addition to introductory Finance and Accounting textbooks, we highly recommend that these candidates read the Street of Walls Investment Banking Technical Training guide, which addresses complex details around Financial Statements, Accounting and Valuation at a very detailed level. (We also recommend this training guide in general to anyone who is interested in advancing their Finance and Accounting skills—particularly when it comes to Corporate Valuation.)

How To Write A Consulting Case Study: Guide, Template, & Examples

When you deliver a successful project, do you publish a consulting case study about it?

A consulting case study is a short story about a successful project that explains…

• The problem your client was dealing with before hiring you;
• your expertise and process for solving that problem;
• and the results your expertise and process created for the client and their business.

In my experience, our consulting case studies are among the most powerful pieces of content we publish. They’re a big reason why people are comfortable signing up for our Clarity Coaching Program .

Because our case studies prove our program helps our clients get results.

I can say that our coaching program is the best on the market until I’m blue in the face.

But it’s much more powerful for consultants to see the results others have experienced for themselves: through our case studies and testimonials.

If you don’t have something of value on your website like a case study — something that actually shows you can achieve results for your clients — then your website will only serve as “confirmational marketing.”

It will confirm what people hear about you. But it won’t help you generate interest and leads.

So, if you want to shift your website beyond mere confirmational marketing to an asset that helps you generate leads and conversions, consider writing consulting case studies using the method below.

In this article, you’ll learn how to write compelling case studies that help you win more consulting clients.

Ready? Let’s dive in…

Your case study is proof that not only can you talk the talk, but you can also walk the walk.

What Is A Consulting Case Study?

When a potential client is deciding on whether they will hire you or not, a big question in their mind is…

“Can this person or company really do what they say they can for my business?”

There are many forms of thought leadership you can use to prove you can deliver results.

The consulting case study is one of them.

A case study, in the context of consulting, is typically a written document that describes…

• the problem a client was facing,
• the actions you took to solve that problem,
• and the outcomes it created for your client.

You write case studies to demonstrate the results and value you created for a past or current client.

What makes them so effective as marketing material?

• They are relatively easy to put together (especially when you use our template below).
• Your potential clients enjoy reading them.
• And they are a highly effective way to demonstrate your authority and expertise in your field.

Next, I’ll walk you through how to write a consulting case study.

In our program, one of the things we teach consultants is how to better understand their clients’ problems and articulate their ability to solve those problems in a way that will attract new clients.

How To Write A Consulting Case Study

Here are the steps to writing your consulting case study. You can follow along with our consulting case study template .

1. Get Permission From The Client

You shouldn’t write a case study that names your client without their permission.

So, before you start writing it, ask them if they’d be OK with you publishing a case study about the project.

Now, I’m not a lawyer, and nothing in this article or anything I write is legal or financial advice. But here’s what we’ve found, through running consulting businesses for over two decades, often works best:

A question we often receive from consultants is “What if I can’t use the name of my client or the company I worked with?” Generally, this isn’t an issue. If your contract says you can’t use the client’s company name, or the client says “No” to your request, all is not lost.

What tends to work extremely well is still writing the case study, but without using the client’s name. Instead, describe the client.

For example, let’s say your client is the automaker Mazda. If you can’t use their name, consider “Working with a top 20 global automaker…”

This gives prospective buyers a good idea of the caliber and type of company you worked with.

When you ask your client for their permission to create a case study that features them, you’ll generally find that 9 times out of 10 they won’t have a problem with you doing so, but make sure you ask before publishing.

2. Introduce The Client’s Business

Once you’ve gotten permission from the client, you’ll begin writing your case study. Follow along using our template .

The first section is the introduction. Set the stage here by introducing your client, their business, and their industry.

This section gives context to the case study. Ideally, your ideal client is intrigued by being in a similar industry or situation as the client in your case study.

3. Describe The Problem Or Challenge

In this section, you outline the problem your client was facing.

Be as specific as you can be.

Simply saying they had marketing issues or a problem with their PR is not enough.

The more detail you include the clearer the picture will become and the more effective your case study copywriting will be.

If your ideal client reads this and has a similar problem as the client in the case study, you can guarantee that their eyes will be glued to the screen, salivating to learn how you solved it.

4. Summarize Your Action Steps

Now that you’ve described the problem your client was up against, you’ll explain what you did to help solve the problem.

In this section, break down each part of the process you used or the steps you took to solve it.

The reader should get the sense that you have a process or system capable of solving the problem and getting results.

This is where you get to demonstrate your know-how and expertise. Get as technical as you can. Show your reader “Hey, this is how I can get YOU results too.”

5. Share The Results

It’s time to demonstrate results.

Write the results that were achieved and how they impacted the business/organization/person.

In many cases, the outcome isn’t just dollars and cents — it can also be less tangible value.

Are they less stressed? Do they have more free time? Are they finding more meaning and enjoyment in their work?

Mention if you’re continuing to work with this client through a retainer . If you’re not, describe how the results will impact their business in the future.

This is also a great place to include a quote or testimonial from your client.

The “Results” section is key because it shows prospective clients that you’ve solved the problems they are facing and have delivered the actual results that they likely desire.

6. Write A Call To Action

At the end of the case study, you should always include a sentence or two inviting the ideal client to reach out.

They’ve just read about the problems you can solve, how you solve them, and the results you can create.

They are primed and ready to reach out to inquire about how you can do it for them.

But if you don’t have a direct call to action for them to do that, many of them will leave without taking action.

So, write a direct, clear call to action that takes them to a page where it’s easy to book a consultation with you or where you provide your contact information.

7. Share It

Marketing for consultants is all about providing value to your ideal clients, being known for something specific, and positioning yourself as an expert and authority that your ideal clients want to work with. So, whenever you publish a piece of valuable content like a case study, your mission is to get as many eyes on the case study as possible.

The best place to publish your case study is on your website or blog.

You can also submit case studies to industry publications. These are a great way to spread the word about you and your client’s business.

Make sure to also share your case study on all social media platforms where your ideal clients hang out online. For consultants, that means LinkedIn.

Work your “marketing muscle” by actively promoting your case study, and you’ll reap the rewards of this powerful piece of authority-building content.

Writing case studies for your consulting business not only helps you land new clients, but it’s also a great way for you to review past projects.

Doing this helps you to find what worked and what didn’t.

And you’ll continue to learn from your experiences and implement your best practices into your next consulting project.

Consulting Case Study Template

Click here to access our Consulting Case Study Template .

This template is designed using a “fill in the blank” style to make it easy for you to put together your case studies.

Save this template for yourself. Use it to follow along with the examples below.

Consulting Case Study Examples

Here are some example case studies from our Clarity Coaching Program clients.

1. Larissa Stoddart

Larissa Stoddart teaches charities and nonprofits how to raise money.

To do that, she provides her clients with a training and coaching program that walks them through twelve modules of content on raising money for their organization, creating a fundraising plan, putting an information management system into place, finding prospects, and asking those prospects for money.

Through her case studies, Larissa provides a comprehensive overview of how she helps her clients build robust fundraising plans and achieve and win more donations.

2. Dan Burgos

Danila “Dan” Burgos is the president and CEO of Alphanova Consulting, which works with US manufacturers to help them increase their profitability through operational improvements.

The goal of Alphanova is to increase their clients’ quality and on-time delivery by 99 percent and help them increase their net profits by over 25 percent.

Through his case studies, Dan lays out the problem, his solution, and the results in a clear simple way.

He makes it very easy for his prospects to envision working with his firm — and then schedule a consultation to make it happen.

3. Vanessa Bennet

Through her company Next Evolution Performance, Vanessa Bennett and her business partner Alex Davides, use neuroscience to help driven business leaders improve their productivity, energy, profitability, and staff retention, while avoiding burnout.

Through her “Clients” page, she provides a list of the specific industries she works with as well as specific case studies from clients within those industries.

She then displays in-depth testimonials that detail the results that her consulting services create for her clients.

These are powerful stories that help Vanessa’s clients see their desired future state — and how her firm is the right choice to help them get there.

As you see, our clients have taken our template and made them work for their unique style, clients, and services.

I encourage you to do the same.

And if you’d benefit from personal, 1-on-1 coaching and support from like-minded consultants, check out our Clarity Coaching Program .

Get Help & Feedback Writing Consulting Case Studies

If writing and demonstrating your authority were easy, then every consultant would be publishing case studies.

But that’s not the case.

Sometimes it helps to have a consulting coach to walk you through each step — and a community of like-minded consultants with whom you can share your work and get feedback from.

That’s why we’ve built the Clarity Coaching Program.

Inside the program, we teach you how to write case studies (among dozens of other critical subjects for consulting business founders).

And we’ve also created a network of coaches and other consultants who are in the trenches — and who are willing to share their hard-fought knowledge with you.

Inside the Clarity Coaching program , we’ve helped over 850 consultants to build a more strategic, profitable, and scalable, consulting business.

LEARN MORE ABOUT CLARITY COACHING

We’ll work hands-on with you to develop a strategic plan and then dive deep and work through your ideal client clarity, strategic messaging, consulting offers, use an effective and proven consulting pricing strategy, help you to increase your fees, business model optimization, and help you to set up your marketing engine and lead generation system to consistently attract ideal clients.

15 thoughts on “ How To Write A Consulting Case Study: Guide, Template, & Examples ”

This is a great outline and I found it quite helpful. Thanks.

Shana – glad you found this post helpful!

I have used case studies to get new clients and you're right, They work.

Jay – thanks for sharing. I've worked with many clients to implement case studies and have used them in several businesses and have always found them to be great at supporting proof and establishing authority and credibility.

Dumb question: guess you can't charge if you're doing a case study, huh?

Terri – No such thing as a dumb question where I come from. Always good to ask.

You definitely can charge for case studies. Michael Stelzner has a lot more information on writing white papers (and case studies) as projects.

This post was really aimed at using case studies to win more business and attract clients. But you can definitely offer this service to companies and they'll pay handsomely for it.

That was a great question!

Hello,I am really glad I stumbled upon your consulting site. This outline is very helpful and I love the e-mails I recieve as well Thanks!

Happy to hear that

This is a great site for consultants – great information for the team to share with consultants that reach out to us. Thank you!

Thanks Deborah

It is a good steps if we know how we start and control our working.

All I wanted to know about putting together a case study I have got. Thanks so much.

to put together your consulting case study: to put together your consulting case study:

I have used your outline today to write one case. Thank you for sharing.

Hi – This is a great piece, and covers all the core elements of a case study with impact.

Couple of extra points…

1. it’s really powerful to provide a mix of qualitative and quantitative results where possible e.g. ‘we saved the client $500 per month and feedback tells us morale improved’

2. We are seeing more and more consultancies include images and video in their case studies. This obviously depends on the context, so while it’s not necessarily appropriate within the confines of a bid, it is definitely something to think about for those case studies that you want to publish online or in a marketing brochure.

Leave a Comment, Join the Conversation! Cancel reply

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• Case Interview Examples 2020 - MyConsultingCoach

Practice makes perfect , and a successful case interview preparation will largely be a matter of practice! Case interview examples are a great resource to build your skills and improve performance. Initially, just reading through (or watching - see below!) example cases will help you understand what you are up against. As your interview preparation progresses, you can start solving these cases yourself and then working with others, using example case studies to simulate full consulting interviews.

To kickstart your preparation,  this article collects a whole host of free case interview examples. We start with what MyConsultingCoach has to offer before going on to look at other useful sources.

Fundamentals: Learning to solve case studies

Of course, before you can get stuck into cases, your first point of action is to get to grips with what exactly case interviews are, what you are up against and how to prepare for them. Our main Guide to Case Interviews is a perfect start here. In particular, we strongly recommend you avoid the old-fashioned case interview frameworks ( Case in Point and Case Interview Secrets are two well known examples), which are still hanging around and trading on name recognition, despite being thoroughly outmoded (we have an article here on why you should avoid Case in Point ).

Prep the right way

Down to Business: Case Practice

Now, once you are up to speed with what you need to know and have learnt how to crack cases in principle, there is no substitute for simply putting in the hours and getting through as many practice cases as you can . Eventually, case cracking should become second nature and you will be ready for whatever your interviewers throw at you!

Case Interview Examples from MCC

Of course, before we go any further, MyConsultingCoach provides a whole suite of case interview examples for you to draw upon. Rather than the standalone "paper" cases we list from outher sources below, our case studies can be used interactively within our meeting board for a significantly enhance

• Free Case Library  - A comprehensive and frequently updated bank of cases covering all styles and subject industries. This is the single best place to practice – whether solo or with a case partner from our meeting board...
• Free Meeting Board - When you practice cases with a partner on our meeting board, our system generates objective, quantified feedback across the key aspects of your case performance - simulating how your interviewer will assess you in real life. On your (free) dashboard on our site, feedback will also be displayed in aggregate over all the cases you have practised. The resulting performance tracker lets you see exactly where you are consistently letting yourself down and our system advises the right next steps to address your weaknesses:

• Video Case Examples : Our Case Academy course has example cases interspersed throughout video lessons, as well as specific lessons running through example entire case studies. Included is the McKinsey style interview-led case which you can watch below:

Case Examples from Elsewhere

Now, whilst we make it our job at MCC to provide everything you need for your case interview prep from A-Z, that's not to say there aren't other example cases out there which might be useful in helping you prepare for your consulting interview. We have collated all the other free case interview resources you may wish to check out. These might be useful, for instance, if you are applying to a specific firm and want to have looked at every available case for them. In total, there are over 2000 free cases here; so plenty to keep you busy!

Where can you find example cases?

There are two main sources of good quality case interview examples. The first is the consulting firms themselves. McKinsey, Bain,  BCG and other major firms want to see candidates at their best and so publish various example case studies on their sites to help familiarise applicants with the interview style and help them prepare. The other major source is business schools/universities and/or the student-run consulting clubs at those institutions. These often produce large numbers of cases to help students prepare to land management consulting jobs after graduation. Here, we collate the best examples from top institutions.

Formats: Casebooks, Interactive Cases and Case Interview Videos

Some cases are published as individual PDFs. However, the numerical bulk of publically available example cases can be found in casebooks. These can be put together both by consulting firms and by university consulting clubs.  As well as a number of example cases, they will often include advice on how to answer case questions in general. In some instances, the cases published by the firms themselves will be interactive for a much more immersive experience. Firms and business schools have also produced some videos either running through case studies or acting out entire case interviews in a realistic setting. These are especially useful to watch at the start of your preparation to get a clear idea of what a case interview is like and what you are preparing for.

Consulting Firm Video Case Examples

These are a great way to get a real feel for what interview day will be like.

Bain, in particular, have a couple of excellent videos showing what case interviews look like and how they are assessed:

LEK also produce some excellent case study videos:

It is worth mentioning that, beyond these example cases, consulting firms often put out a great deal of other useful video content, covering other aspects of the selection process as well as like in the firm and explaining consulting projects they have been engaged on. As such, consultancies' YouTube and similar content can be well worth a look for applicants. Certainly, the video format can help to give you a better "feel" for the companies and the subjects they are talking about beyond simply reading cold, hard text.

Individual Cases from Consultancies

Now, on to more typical sample cases. We’ll start with individual cases. Some of these are simply PDF downloads, but several are more immersive, interactive experiences.

• A T Kearney Promotion Planning Case Question
• BCG Genco Case Question
• BCG Foods Inc Case Question
• Deloitte Finance Strategy Case Question
• Deloitte Retail Strategy Case Question
• McKinsey National Education Case Question
• McKinsey GlobaPharm Case Question
• McKinsey Electro-Light Case Question
• McKinsey Diconsa Case Question
• OC&C Leisure Club Case Question
• OC&C Imported Spirits Case Question
• Oliver Wyman Aqualine Case Question
• Oliver Wyman Wumbleworld Case Question

Everything you need in one place

Firm Casebooks and Case Interview Guides

 Some of these casebooks are also interactive and generally should be required reading if you are applying to one of these firms.

• AT Kearney Consulting Casebook
• Accenture Casebook
• BCG Interactive Case Library
• Bain Interview Guide and Case Library
• Bain Written Case Guide
• Capital One Case Study Guide
• PWC Strategy& University Presentation (including case questions)

University Casebooks

Where business schools and their consulting clubs excel is in generating very large numbers of cases. These migth not be interactive, but provide plenty of material for those taking a "brute force" approach of crunching through as many case studies as possible.

• UC Berkeley Consulting Casebook 2006
• Columbia Business School Consulting Casebook
• Darden School of Business Consulting Casebook
• Duke University
• 2011 Duke Consulting Casebook
• 2014 Duke Consulting Casebook
• ESADE Consulting Casebook
• Goizueta Business School Consulting Casebook
• University of Illinois Consulting Casebook
• London Business School Consulting Casebook
• MIT Consulting Casebook
• University of Notre Dame Consulting Casebook
• Ross School of Business Consulting Casebook
• Wharton Consulting Casebook

University Case Videos

A few business schools and consulting clubs have created genuinely useful case interview videos. A couple of the better examples are shown below. Production standards can be slightly lower than their corporate equivalents, but the content remains excellent.

Kenan-Flagler

This is the first in a series of videos from the Kenan-Flagler Consulting Club, which you can view in full here .

Prepping the right way

Mastering case cracking is a lot like learning a language. The more you practice, the better - however, that practice will be no good if you don't have the basics in place first . Someone who doesn't speak a word of Russian could listen to Russian radio all day every day for a year and learn nothing. However, if they already had the basics of vocabulary and grammar in place, listening to Russian radio would be a great way to cement and build their understanding of that language.

Precisely the same is true of case studies - you need to understand how to solve them properly before practice will be really useful.

The best place to get all the business background (your consulting "vocabulary") and reasoning skills (your consulting "grammar") is with our MCC Academy case interview course. There we take you from finance and accounting basics, right through advanced reasoning skills, consulting math and our Problem Driven Structure case method . Far from the old-fashioned, unreliable frameworks many unsuccessful candidates prep with, our method has been devised as a streamlined, four-step version of the seven-step roadmap used by McKinsey consultants on real engagements.

You can learn more about MCC Academy here , as well as in the video below:

Practice with the best

Practising with a partner - perhaps one from o ur meeting board - beats practising solo. However, with the best will in the world, there is only so much you and another candidate with no actual consulting experience are going to be able to give one another in terms of feedback.

If you have invested the time to learn how to crack cases properly, it makes sense to then practice properly as well. The very best way to simulate a real consulting interview and to receive the kind of detailed feedback to really get up to the required level is to practice with a real consultant . Nobody else will be able to give you better feedback or help you progress so rapidly. Indeed, we find that receiving professional case coaching is the single largest difference-maker in terms of candidates landing job offers .

MyConsultingCoach offers the best quality coaching experience on the market . Instead of some shady directory of unvetted freelancers, we select all our coaches to have at least two year's consulting experience with either McKinsey, Bain or BCG, as well as existing coaching expertise. Our coaching experience is then designed to sync with the MCC Academy and other resources, providing a seamless learning experience.

Our feedback is provided via our advanced Performance Radar tool. This combines your coach's qualitative feedback with a statistical, quantitative assessment of your progress across key areas - just like we showed for our meeting board above, but assessed directly by a real, MBB consultant. This ensures you know exactly which skill areas to target, with MCC learning resources ready to help you do so.

Learn more about our coaching here.

Mentoring: Maximal Efficiency and Complete Peace of Mind

For those of you are taking your prep truly seriously, MyConsultingCoach also offers comprehensive mentoring programmes. Here, an experienced MBB consultant takes personal charge of planning and overseeing your whole preparation; editing your resume and cover letter if required, guiding you through our course material and planning when you should be having coaching sessions.

Not only does this offer the best possible chance of successfully landing a job, but it is also the most efficient way to use the time you have to prepare. This is especially important for time-poor professionals aiming to transition to management consulting from other high-workload jobs - or for busy students trying to balance interview prep with studying for finals. Where your time is scarce, you need to make sure that every hour you can spend on prep is used optimally.

Looking for an all-inclusive, peace of mind program?

Candidates who sign up to our free services are 3 times more likely to land a job in one of their target firms . How?

• We teach how to solve cases like consultants , not through frameworks
• Our Meeting Board lets you practice with peers on 100+ realistic, interactive cases.
• Our AI mentor creates a personalised study roadmap to give you direction.
• All the advice you need on resume, cover letter and networking.

We believe in fostering talent, that’s why all of the above is free .

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Consulting Case Study Template

Illustrate your consulting success with the informative Consulting Case Study Template – emphasize project wins, solutions, and client satisfaction.

About this template

Showcase your consulting expertise with our Consulting Case Study Template. Highlighting successful projects, innovative solutions, and client satisfaction, this template builds credibility and trust with potential clients.

Illustrate the real-world impact of your consulting solutions and foster trust among prospective clients. Our Consulting Case Study Template enables you to present your success stories effectively, positioning your consulting business as a leader in the industry.

What's included?

• Scope of work

About the author

Jess Tassell | Fractional CMO

Jess is the Fractional CMO at Qwilr, looking after product marketing, growth, content functions and more. Prior to Qwilr, Jess was the International CMO of StubHub International (eBay owned $5B marketplace), where she led a team of 44 marketers across 69 markets. Jess also has extensive strategy consulting experience in Australia and the United States from starting her career at EY.

What is a Consulting Case Study?

A Consulting Case Study is a document or report that presents a detailed analysis of a particular project, business problem, or scenario that a consultant or consulting firm has worked on in the past. The purpose of a case study is to illustrate the consultant's or consulting firm's approach to problem-solving, showcase their expertise, and demonstrate the value and results they can deliver to their clients.

Here's a brief outline of what a typical Consulting Case Study might include:

• Introduction : This is where you give a brief overview of the client – who they are, what they do, and what their business landscape looks like. You might also discuss why they approached you for consulting services.
• Problem/Challenge : This section will outline the specific problem or challenge the client was facing. This could be anything from a decrease in sales, a need for a technology overhaul, or difficulties in strategic planning. It's important to be detailed in explaining the complexity of the problem to highlight the depth of your problem-solving capabilities.
• Approach/Solution : This might include the methodologies or frameworks used, team members involved, and the timeline of your work. This is your chance to illustrate your unique approach to problem-solving.
• Results : In this section, you present the outcome of your work – the concrete results or improvements seen by the client due to your consulting services. The more specific and quantifiable the results, the better. This could be improved sales numbers, cost savings, improved operational efficiency, etc.
• Conclusion/Testimonial : Finally, you conclude the case study with a summary of the project and the results achieved. If possible, include a testimonial from the client. This not only enhances the credibility of the case study but also provides prospective clients with a firsthand account of your work.

When should you use case studies in consulting projects?

As a consultant, you can use case studies to persuade potential clients to sign up for your services, showcase your expertise to existing clients, and share your success stories with your network. You can use case studies when:

• You want to illustrate your consulting process and methodology.
• You want to demonstrate the positive impact of your services on a client's business.
• You want to showcase your solutions to a particular industry's challenges and highlight your industry-specific expertise.

Benefits of using Qwilr's Consulting Case Study Template?

Writing a consulting case study from scratch can be time-consuming, especially if you're not familiar with the format and structure. However, with Qwilr's consulting case study template, you can create a professional-looking and effective case study in no time. Here are some benefits of using Qwilr's template:

• It is visually appealing and customizable to match your brand's colors and aesthetic.
• It is interactive and allows you to include multimedia elements like videos, images, and charts to showcase your data and results effectively.
• It is mobile-responsive, making it easy to share with potential clients on any device.
• It is easy to use, even for non-designers.

How do you use Qwilr's Consulting Case Study Template?

Using Qwilr's consulting case study template is easy. Here are the steps:

• Sign up for a Qwilr account.
• Select the consulting case study template from the template gallery.
• Customize the template to match your brand's colors and aesthetic.
• Edit the sections to include your project description, challenges, solutions, and results.
• Add multimedia elements like images, videos, and charts to showcase your data and results effectively.
• Share the case study with your network using a shareable link or downloading it as a PDF.

A tool packed with features

Brand control.

Establish your brand settings once and automatically apply to every piece of collateral.

Collect payments instantly from customers with Stripe or direct to your own payment system.

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Add security features like password protection and link expiry to protect sensitive content.

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Add Calendly links, videos, surveys, Looms, GIFs and more to every page.

E-signature

Get deals signed on the spot with built-in e-signing ability.

Asset library

Create a library of reusable content for sales reps.

ROI calculator

Showcase your value with an interactive ROI calculator embedded in your Qwilr pages.

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Set up permissions so your team accesses only what they need.

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Empower buyers with interactive pricing plans and quotes.

Templates for every use case

Explore templates for sales, marketing, customer success, sales enablement and more.

• All templates
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• Online brochure

Frequently asked questions

How do you write a consulting case study.

Writing a consulting case study can be challenging, especially if you’re not sure where to start. Here are some tips on how to write a compelling and effective consulting case study:

• Start with a clear and concise introduction that outlines the client's problem and your proposed solution.
• Describe your proposed solution in detail, including your methodology, timeline, and budget.
• Include visuals like images, videos, and charts to showcase your data and results effectively.
• Highlight the positive impact of your services on the client’s business, including any measurable results like increased revenue, improved customer satisfaction, or cost savings.
• Close with a summary of the outcomes and a call-to-action for potential clients.

How do you structure a consulting case study?

Structuring a consulting case study is essential to make it easy to read and understand. Here is a recommended structure for a consulting case study:

• Introduction: Introduce the client's problem and your proposed solution.
• Context: Describe the client's industry, market position, and competitive landscape.
• Challenges: Outline the specific challenges the client faced and how they impacted their business.
• Solutions: Describe your proposed solutions, including your methodology, timeline, and budget.
• Results: Highlight the positive impact of your services on the client's business, including any measurable outcomes like increased revenue or customer satisfaction.
• Conclusion: Summarize the outcomes and provide a call-to-action for potential clients.

What's important to include in a consulting case study?

When writing a consulting case study, it's crucial to include the following elements:

• An introduction that outlines the client's problem and your proposed solution.
• Specific details on the challenges your client faced.
• A clear explanation of your proposed solutions, including your methodology.
• Data and metrics to demonstrate the positive impact of your services.
• A summary of the outcomes and a call-to-action for potential clients.

Written Case Interview - Everything You Need to Know [2022]

• Last Updated December, 2023

Rebecca Smith-Allen

Former McKinsey Engagement Manager

Why Do Firms Use the Written Case?

How Should Candidates Approach the Written Case?

Bain Written Case - What to Expect

Tips to Feel Confident in the Written Case

Are Written Cases Different from Case Questions?

The written case interview is less common than the typical case study interview, which is conducted one-on-one with an interviewer. But even top firms like Bain and BCG use them in some geographic regions, so you’ll want to be prepared for them.

The good news is that the written case is just a different form of the case interview. If you’ve been preparing for the case study interview , then you have the foundations to pass the written case as well. But the things you need to do to ace a written case are not exactly the same as a normal case.

In this article, we’ll provide:

• An overview of the Bain and BCG written case interviews,
• Tell you how they’re structured,
• Share our 9 tips on written case study interviews, and
• Tell you how you should prepare for these types of cases.

Why Do Bain and BCG Use Written Case Study Questions?

Some people are great at talking. Some people are great at writing. To succeed in consulting, you need to be pretty strong at both.

Bain and BCG use written case study interviews to make sure they hire consultants that can absorb key facts whether the data is provided in a conversation or in writing. They’re also looking to see whether you can go through large amounts of data quickly and whether your written communication is effective.

In a written case interview, your interviewer is still looking for the same key problem-solving skills:

• Can you frame the question that needs to be answered?
• Can you drive the discussion of the options open to the client?
• Can you do the quantitative analysis required to support your problems solving?
• Do you display good business judgment in your recommendation?

[EXCLUSIVE FREE TRAINING]

• 3 strategies to pass the case in under a week;
• A proven process for taking your casing from "average" to "exceptional";
• Tips from a McKinsey Engagement Manager on how to land the offer.

Bain Written Case Study Questions — What to Expect

Your written case study at Bain will start with you receiving 20-30 PowerPoint slides that describe a client’s situation .

You’ll have 55 minutes to read the slides, pull key data and insights from the material, and handwrite missing data into 3-5 slides provided to you.

You’ll then meet with one or more Bain interviewers  for about 40 minutes to discuss your analysis and recommendations. During the first half of this time, you’ll present your slides. During the second half, your interviewer will ask questions.

Your interview may challenge your assumptions or conclusions. This does not necessarily mean that you got the “wrong” answer. It only means that your interviewer wants to test whether you can support your recommendations when pressed. 

Over the course of a 6-month study, things change. Your interviewer wants to know that when they do, you’ll be able to react to the situation in a way that shows your insight into the problem, not panic.

As mentioned above, you’ll get a few slides that contain some pre-filled information but they are not complete. These slides might have a title and be otherwise blank. In this case, you’ll be required to find the appropriate information to support the title and to create the page. 

Alternatively, these slides might have graphs and tables that require data to be filled in. In this case, you need to find the information required and do the appropriate calculations to provide the missing numbers.

The good news is that because you’re provided direction on what belongs on the page, you don’t need to create a storyline for the presentation or decide how many pages to present.

During the Bain case interview you are not allowed to use a calculator.  

The quantitative problems in the written cases are not complicated, but your interviewer is looking to see that you can do basic analysis correctly.

Which Candidates Get a Bain Written Case Interview?

Not all Bain recruits are given written case interviews. They’re primarily used in the European and Asian offices, not in North America. They’re very common in Bain’s Greater China offices.

Any recruits—undergraduates, business school students and people looking to transition to consulting from jobs in other fields—could all be given written case interviews. People applying for summer internships could as well.

Bain uses written cases in final round interviews , not the first round. The final round interviews will include a fit interview as well as a written case.

The written cases count as much as “normal” cases do. They can involve any industry and any type of client problem

BCG Written Case Study Questions — What to Expect

The BCG written case question is structured like an email written by a partner at the firm. In the email, the partner asks you to answer 3-4 questions. He or she wants you to prepare slides that could be used to discuss the issues with the client. 

Along with the email, a slide packet of about 40 pages will be provided. These slides will include data charts, graphs, and text. 

You’ll have 2 hours to go through the information you’re provided on your own and create the slides. However, with 40 slides of dense information in your hands, you could easily spend the entire 2 hours just reading and not have anything to show your interviewer. 

Use your time efficiently , skimming for information that’s directly relevant to the questions you were asked to answer. 

Your packet will include a few blank pieces of paper to use to create the slides that answer the partner’s question. Because these pages are blank, you’ll have to decide how many slides to create and how to structure them. This puts a lot more pressure on you to decide how to shape the story about the solution to the client’s business problem than in the Bain written case.

A couple more small but important points:

You’re allowed to use a calculator during the BCG written case interview.

You’re not allowed to write on the slides you’re given because BCG uses the se same slides with other candidates. This can be challenging because you won’t be able to make notes on the slides you’ve pulled data from in case you want to go back and reference it.

After the 2 hours working on your own, you’ll have a 40-minute discussion with an interviewer . 

• During the first 20 minutes: you’ll present your slides to the consultant.
• During the second: they’ll ask you questions about your analysis and conclusions.

Which Candidates Get a BCG Written Case Interview?

BCG does not use written cases in all of its locations. We’ve heard of BCG using written cases in U.S. offices, Russia, Sweden, the Netherlands, and South Africa.

When they do use written cases, it’s always in the second round of interviews and you will know well ahead of time to prepare for them, so no need to worry if it will be a surprise come interview day.

What Are the Differences Between the Bain and BCG Written Case Study Interview Assessments?

The Bain written case is shorter both in terms of the number of slides you’ll need to sort through for information and in terms of the time you have to work on your own. 

The Bain written case also provides slides that are partially filled in, which you will need to complete.

You are not allowed to use a calculator on the Bain written case interview but you are allowed to on the BCG written case interview. 

For the BCG written case, you’ll have more slides to sort through and more time to do it. You’ll be provided with blank slides on which you can provide your answers to the questions from the partner’s email.

Are Written Case Questions Different from Normal Cases?

Written cases are similar to normal cases. The interviewer is still assessing how you structure and solve a business problem.

There are 4 key differences though:

• There’s too much information. The 20-40 slides you’re given will provide more information than you need. Sift quickly through the data to find the information most relevant to the question you need to answer. This tests a skill that is directly applicable to real-world consulting. Clients have tons of data, but if you ask for everything that could possibly be relevant, you’ll take so long answering the question that it could be irrelevant by the time you reach it. You need to sort through what is worth your time and what to set aside.
• You’ll need to focus on your recommendation. In our article on Case Interview Examples , MyConsultingOffer.org founder, Davis Nguyen, discusses the 4 key parts of the case interview , the opening, the structure, the analysis, and the closing. In written cases, focus on the closing or recommendation for the client. You’ll discuss other aspects of the case when you meet with your interviewer.

Don’t use the slides to describe how you did the work.

Don’t document every step you went through to reach your conclusion or every calculation you did. Use headings that speak to the steps you recommend the client takes. On graphs or charts, headings should speak to the implications of data, not simply regurgitate what the chart shows. 

What Written Case Study Questions Tell You About the Job of a Junior Consultant

Look at the structure of the Bain and BCG written cases:

• You get an email from a partner who’s not available to answer questions when you start your work, or
• You’re given a huge pile of data with slides that roughly outline the analysis to be done,
• You’re responsible for quickly finding the key data, doing the analysis and creating the PowerPoint slides for the client meeting.

This is actually a fair representation of the work new consultants do at any of the top consulting firms. Partners work with multiple clients so they will not be around to tell you exactly what to do and how to do it. 

A great consultant will work independently finding and analyzing data and creating slides.

Because of this, a written case is a great second round interview. It will tell your interviewer a lot about how well you’ll perform in the job. It will also give you good insight into what the job is like.

Written Case Study Interview Examples

• Which market should the client enter? Why is this market attractive?
• What would the competitive advantages and disadvantages of the client’s product be in the new market?

A written case study question could focus on any industry and any geographic region, just like a normal case study can.

Writing PowerPoint Slides – The Best Approach

In our intro page on Case Study Interview Prep , we talk about the 4-part process for answering a case. 

The one time we don’t recommend you use this approach is on written case study questions.

If you go through the 4-part process for answering a “normal” case in your PowerPoint slides, you’ll spend too much time on less important topics and not enough on your recommendation for the client. Instead, turn the structure around and start with your conclusion or recommendation. We recommend your written slides follow the following 5 R outline:

• Recap the question.
• State your recommendation.
• Provide the reasoning behind your recommendation.
• Outline any risks to your recommendation.
• Retain the client by suggesting next steps.

Below, we’ll provide more detail on each point.

1. Recap the question.

This is a simple step but it ensures that everyone is focused on the same goal. Don’t skip this step even though it seems obvious.

2. State your recommendation.

The best way to move the discussion forward efficiently and keep the interviewer (and your future consulting clients) focused on what you’re saying rather than on guessing what’s coming next is to simply lead with your answer. 

3. Provide the reasoning behind your recommendation.

Now is the time to show that you thought through your solution and crunched all the necessary numbers. Create a slide with the data behind each supporting argument.

4. Outline any risks to your recommendation.

Many recruits can do steps 1-3. Their computations are correct and they come up with a reasonable recommendation. What will set your written case study answer apart? 

Going above and beyond the average answer. One way to do this is by outlining risks.

Whoa, you might say, if I talk about risks won’t my answer sound weaker?

First of all, any senior business leader knows that all business decisions come with risks. There is risk in doing nothing because your competitors will act faster and come out with better products or better marketing plans. 

There is also risk in acting fast because you might find that with imperfect information, you didn’t make the best possible decision.

But knowing what risks are the most relevant to a business situation will help the client minimize the risks or avoid them altogether.

5. Retain the client by suggesting next steps.

Like outlining risks, suggesting next steps is a way to go beyond the basic answer most recruits provide. In particular, you want to show how you can help with the next steps.

Consultants make money by providing support to their clients. If there are ways that you can help the client with the next stage of the project, that will also create more interesting work for you and continue to help your client’s business.

What Does this Approach to Writing PowerPoint Slides Look Like?

• 1st slide: Client Should Take Recommended Action for the Following 3 Reasons.
• 2nd slide: Outline reason #1. The slide should provide charts or data that support the statement.
• 3rd slide: Outline reason #2. The slide should provide charts or data that support the statement.
• 4th slide: Outline #3. The slide should provide charts or data that support the statement.
• 5th slide: Recap the Recommendation – emphasizing benefits but touching on risks and how the consultant can help with next steps.

9 Tips for Solving Written Case Study Questions

1 | Contact your recruiter or prior applicants to get a solid understanding of the written case. Will you be expected to complete slides provides or write slides from scratch? How long is the preparation time, presentation time, and Q&A time? Who will you be presenting to?

2 |  Focus on the question you need to answer. If you start with the end in mind, it will help you zero in on the information that will drive the answer to the client’s question. It will also help you discard irrelevant facts.

3 | Develop a hypothesis you can prove or disprove. A strong hypothesis will keep you focused on finding data and anecdotes that are relevant.

4 | Prioritize relevant data. Not all facts or slides are equally important. Focus on the key issues and avoid getting lost in the weeds.

5 |  Analyze key numbers. Figure out what data is important for the decision the client must make and perform necessary calculations. Ignore the rest of the data.

6 |  Structure your slides as a client recommendation. While the “normal” case has 4 stages: the opening, the structure, the analysis, and the conclusion, your written case study answer should start with the conclusion or recommendation.

What should the client do? Don’t waste time describing the tables you created or the calculations you did if they have no bearing on your recommendation. Everyone assumes you can do the math. What they care about is the “so what” that comes out of the math.

7 | Keep an eye on the time. It’s important to make sure you have enough time to write your slides. Allocate the time you’re given to skimming the slides provided for information, doing necessary calculations, and drafting slides. Make sure you don’t run over on reading slides.

Optimally, you’ll want to leave a few minutes to think through how you’ll present the slides to your interviewer as well.

8 | Remember there is no “right” answer. The key to this interview is to make a well-reasoned recommendation and have a rich discussion about how to achieve results for your client. 

Everyone gets nervous during an interview, but second-guessing whether your recommendation is right or wrong will only waste time. Instead, focus on making your argument for the recommendation you’ve chosen as strong as it can be.

9 | Conclude with insights that go beyond the average answer to the case. As mentioned above, most recruits will get the math right and present a reasonable recommendation. Go beyond this by highlighting risks that the client should be aware of as they implement your recommendation and ways your consulting team can continue to assist the client through the next steps. 

How Should Candidates Approach Written Case Study Practice?

Learn to write presentations like a consultant..

The key to writing presentations like a consultant is to tell a story. Use the 5R framework from above t o create your story.

Start with your recommendation to the client. Back up your recommendation with supporting arguments and the data that lead you to them.

Use message headings rather than titles that just repeat the data in a  chart.

Chart Title: Product C has higher sales than products A or B.

Message Heading: Product C’s success in the domestic market indicated that it is the best product to launch into the new market.

Practice your consulting math skills.

If your basic math skills are rusty and making you nervous, that will slow you down in any case interview. Rusty math skills can be particularly problematic in a written case because there will be no interviewer to coach you that you’ve made a mistake until your slides are already written. Bad math could cause you to create slides with the wrong recommendation and that would be difficult to recover from. 

See our page on  Case Interview Math   for more information on what types of calculations case study questions typically ask for and tips on how to practice.

Preview written case interviews.

Just knowing what to expect in a written case interview is a huge advantage. Take a look at the resources listed in the next section. Reviewing a couple of BCG or Bain written cases will make you feel more confident and allow you to answer the question faster once you’re in the interview.

Additional Resources on Written Case Study Questions

For more information on written case study questions, see:

This Bain video or  BCG’s Guided Consulting Cases .

In this article, you’ve learned about both the Bain written cases and the BCG written cases. You’ve learned what the format is, what to expect and how to prepare for these written case study interview questions. 

We hope you ace that written case!

Still have questions??

If you have more questions about written case interviews, leave them in the comments below. One of My Consulting Offer’s Bain or BCG case coaches will answer them.

Other pages people preparing for written case study interviews found helpful include:

• Group Case Interviews ,
• BCG Online Case , and
• Market Sizing Questions .

Want to feel confident walking into your written case interview? Find out how.

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