Prep · McKinsey
McKinsey case math
McKinsey case interviews embed math directly into the case discussion. There's no separate 'math test' — you'll be asked to calculate mid-conversation while your interviewer watches. Speed and composure matter as much as accuracy.
Interview format
Solve Game
Online assessment that replaced the PST in most offices. Tests problem-solving through ecosystem simulation and data interpretation.
Case interviews
2-3 rounds, each with 1-2 cases. Math is woven into the case — you calculate while discussing, not in isolation.
PEI (Personal Experience Interview)
Behavioral questions. No math, but happens alongside case rounds.
What McKinsey tests in math
McKinsey cases lean heavily on market sizing and profitability. You'll be asked to size markets, calculate margins, and assess whether a strategy is financially viable — all while structuring your thinking out loud. The math is rarely harder than difficulty 3, but the speed expectation is high because you're calculating during a conversation.
What to practice
Market sizing — McKinsey's most common math type. Practice breaking markets into segments and multiplying quickly.
Margin and profitability — 'Revenue is X, costs are Y, what's the margin?' should take under 5 seconds.
Mental arithmetic composure — Practice calculating while talking. CaseBlitz drills train exactly this.
Estimation and rounding — McKinsey interviewers prefer directionally correct fast answers over precise slow ones.
Insider tip
McKinsey interviewers often give you data and watch how you react. Practice seeing numbers and immediately identifying what calculation to run — before being asked.
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CaseBlitz trains the exact math types McKinsey interviews demand. 5 questions a day, timed to interview speed. Start with a free diagnostic.
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