Case Interview Math Speed Trainer
Timed mental math drills for consulting candidates. Practice the exact calculations tested at McKinsey, BCG, Bain, and Big 4 firms.
Ready to practice?
Select a category and difficulty, then click Start Drill to begin. You'll have 45 seconds per problem.
Current: Percentage & Growth · Medium · 45s timer
Session Stats
Streak
💡 Pro Tip
Round to friendly numbers first, then adjust. 23% of $412M → think 25% of $400M = $100M, then refine to ~$95M.
Frequently Asked Questions
What types of math are tested in case interviews?
Case interviews primarily test mental math involving percentages, growth rates, profitability analysis (margins, break-even), market sizing estimates, and compound growth (CAGR). You rarely need advanced math — speed and accuracy with basic arithmetic are what matter most.
How fast should I be able to solve case math problems?
Top consulting candidates solve basic percentage and margin calculations in under 30 seconds and more complex problems (CAGR, multi-step market sizing) in 60-90 seconds. Our drill timer helps you build speed toward these benchmarks.
How can I improve my mental math for consulting interviews?
Practice daily with timed drills focusing on your weakest categories. Learn shortcut techniques: the Rule of 72 for CAGR, rounding to friendly numbers, and breaking complex calculations into smaller steps. Consistency beats cramming — aim for 15-20 minutes daily.
Do BCG, Bain, and McKinsey test the same math skills?
Yes, all MBB firms test similar quantitative skills in case interviews. The math itself is consistent — percentages, margins, growth rates, and market sizing. The difference is format: McKinsey uses interviewer-led cases while BCG and Bain tend to be more candidate-led, but the underlying math expectations are identical.
Preparing for McKinsey Solve?
Math drills are one part of the puzzle. McKinsey's Solve assessment has a ~20% pass rate — our AI simulators give you the practice edge other candidates don't have.