Case Interview Maths McKinsey

Case Interview case math First Round McKinsey
New answer on Apr 22, 2022
2 Answers
Anonymous A asked on Apr 22, 2022

Hi everyone, 

I thought it can be a good idea to create a list for the quantitative part of the case at McKinsey (all maths possibility questions). Please feel free to add more to the list 

1) ask you to calculate cost savings 

2) ask you to calculate the gross margin 

3) ask you to calculate the price point to break even 

4) ask you to calculate how many units must be sold to breakeven 

5) ROI 

6) how to achieve a specific amount of ROI 

7) payback period 

8) ask you to calculate the market share whilst only providing population, market share of another country, and the 1% of market share of that country 

9) ask you to calculate the output ? (not sure) 

10) market sizing 

11) CAGR? or calculate x using CAGR numbers (not sure) 

12) should we expect NPV calculation??


Overview of answers

  • Upvotes
  • Date ascending
  • Date descending
Best answer
Content Creator
replied on Apr 22, 2022
#1 rated McKinsey Case and PEI Coach | 5 years at McKinsey | Mentorship Approach | 120+ McK offers in 18 months

Hey there,

I agree with Ian here.

Its a noble effort but it won't get you very far for two reasons:

  1. You will never be able to collect all the possible math problems there are.
  2. Even if, let's say your case includes a breakeven calculation, it could be asked in a way that is not entirely clear from the start what you need to do and there might be different potential approaches that could work. Interviewers won't ask ‘’can you calculate the break-even here'' but they will package it into a more obscure question in the context of the case that you need to figure out how to approach.

As a result, trying to anticipate what kind of case you will get (industry, function, problem) or what math problem you could potentially get only sets you up for failure as for McKinsey it's all about how you approach a problem. That is also why a cookie-cutter approach usually does not work.

I have seen it many times over that people who focus on the what rather than the how to get into this spiral:

False sense of security > go to the interviews > it does not go their way since they expected something different > try to fit something into the answer that does not fit / overlook a much simpler or more elegant way to approach the problem > panic > rejection.

Rather focus on working on your core math and quantitative reasoning skills. This will build a holistic understanding of the logic, which is the foundation to solving every quant problem. 


Was this answer helpful?
Content Creator
replied on Apr 22, 2022
MBB | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep

Hi there,

It's definitely good to have a list and this is a good start!

That said, even if you had a list of 1,000 you wouldn't be completely covered! Definitely practice and build up your repertoire, but also remember this is less about memorization and more about learning how to think through problems! Make sure you know how to break down whatever math problem comes your way.

Was this answer helpful?
Anonymous B on Apr 22, 2022

Such a BCG answer…

Ian on Apr 24, 2022

Apparently a McKinsey answer as well! (per the other response). It's your call as to whether you'd like to take the memorization path or the LEARNING path - one will only get you so far! (There's a reason my candidates succeed at higher rates than most)


Florian gave the best answer


Content Creator
#1 rated McKinsey Case and PEI Coach | 5 years at McKinsey | Mentorship Approach | 120+ McK offers in 18 months
Q&A Upvotes
309 Reviews