Practice · Market Sizing
Market sizing questions
Market sizing questions test your ability to structure an estimation and execute clean arithmetic under pressure. Every MBB firm tests this — it's the most common math type in first-round cases.
Why interviewers test this
Interviewers use market sizing to evaluate two things simultaneously: your ability to decompose a problem into logical components, and your comfort with back-of-envelope arithmetic. The math itself is rarely hard — the challenge is maintaining structure while calculating.
Worked examples
The European coffee market is €80B. Your client has 2.5% share. What is their revenue?
€80B × 2.5% = €80B × 0.025 = €2B. Shortcut: 2.5% is half of 5%, and 5% of €80B is €4B, so half is €2B.
A city has 2M households. 60% own cars. Average 1.4 cars per car-owning household. How many cars?
2M × 60% = 1.2M car-owning households. 1.2M × 1.4 = 1.68M cars. Round to 1.7M in an interview.
Strategies
Round aggressively — 1.68M becomes 1.7M. Precision wastes time and doesn't impress.
Work in millions or billions, never in raw numbers. Say '2 billion' not '2,000,000,000'.
Sanity check your answer. Does 1.7M cars in a city of 2M households feel right? Yes — about 0.85 cars per household.
Break complex percentages into parts: 17.5% = 10% + 5% + 2.5%.
Difficulty 1-3. At easy levels, it's single multiplication. At hard levels, it's multi-step with unit conversions.
Practice market sizing under pressure
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