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How to define time before break even

Case Interview
New answer on Nov 11, 2023
2 Answers
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Anonymous A asked on Jun 18, 2017


There are often cases when interviewer asks to determine the price of newly developed product. If R&D costs are significat, I always tend to do break even analysis and price always becomes to depend on time period, in which one wants new product ro break even. (I had case where I could freely choose price, varying break even time period between 3 and 20 years).

What are the criterias one should consider to decide the right time period for break even. Should I ask the interviewer when client wants to break even? What if I am asked about reasonable time period for break even.

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Content Creator
replied on Nov 11, 2023
McKinsey | Awarded professor at Master in Management @ IE | MBA at MIT |+180 students coached | Integrated FIT Guide aut


Precisely for the high amount of questions (1) asked by my coachees and students and (2) present in this Q&A, I created the “Math & Formulas - Economic and Financial concepts for MBB interviews”, recently published in PrepLounge’s shop (

After +5 years of candidate coaching and university teaching, and after having seen hundreds of cases, I realized that the economic-related knowledge needed to master case interviews is not much, and not complex. However, you need to know where to focus! Hence, I created the guide that I wish I could have had, summarizing the most important economic and financial concepts needed to solve consulting cases, combining key concepts theorical reviews and a hands-on methodology with examples and ad-hoc practice cases.

It focuses on 4 core topics, divided in chapters (each of them ranked in scale of importance, to help you maximize your time in short preparations):

  • Economic concepts: Profitability equation, Break even, Valuation methods (economic, market and asset), Payback period, NPV and IRR, + 3 practice cases to put it all together in a practical way. 
  • Financial concepts: Balance sheet, Income statement/P&L and Performance ratios (based on sales and based on investment), +1 practice case
  • Market structure & pricing: Market types, Perfect competition markets (demand and supply), Willingness to pay, Pricing approaches, Market segmentation and Price elasticity of demand, +1 practice case
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Content Creator
replied on Jun 19, 2017
#1 Coach for Sessions (4.500+) | 1.500+ 5-Star Reviews | Proven Success (➡ | Ex BCG | 10Y+ Coaching

Hi Anonymous,

as you mentioned, there are two potential options for such a problem:

Option 1: you get the information from the interviewer, that is, either they provide the information at the beginning or you ask for that (which you are definitely allowed to do). You could receive the information as:

  • The relevant period of time directly (eg 5 years) or
  • The minimum return per year desired (eg 5%), which would allow you to compute such period of time (if you have to reach €5M back investing €5M, and the desired minimum return per year is 5%, then you would reach the target in maximum 20 years with simple interest and no discount factor, as given solving the following formula: 5M*0,05*x=5M).

Option 2: you have to estimate the right period of time. In this case, the best option is to consider which is the opportunity cost for the company if it would have to invest the money in a comparable risky option; usually, this information is provided as expected return of the alternatives. You can then use such an interest rate as before to compute the maximum period to reach the target.

As an example, if your goal is still to reach €5M back with an investment of €5M, and you know the minimum return for an equivalent risky option is 10%, then you know you would have to reach you goal in maximum 10 years, using the same math formula as before. If the alternative is less risky, you would then have to reach it in less then 10 years, to compensate for the higher risk, while if it is more risky, you could reach it in more then 10 years for the same reason, unless there are additional constraints in the case.

Hope this helps,


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Content Creator
McKinsey | Awarded professor at Master in Management @ IE | MBA at MIT |+180 students coached | Integrated FIT Guide aut
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