McKinsey Interview Prep: Case Study & PEI Guide 2026

McKinsey Interview Prep: Case Study & PEI Guide 2026

McKinsey interviews are among the most rigorous in any industry. The format: case study problem-solving + Personal Experience Interview (PEI). Here's the complete preparation guide.

McKinsey Interview Format

• Round 1 (2 interviews): 1 case study + 1 PEI each
• Round 2 (2-3 interviews): More complex cases + deeper PEI
• McKinsey Solve: Online problem-solving assessment (before interviews)

Case Study Frameworks

• Profitability — Revenue (price × volume) vs Costs (fixed + variable)
• Market Entry — Market attractiveness + competitive landscape + capabilities
• M&A — Standalone value + synergies + integration risks
• Market Sizing — Top-down or bottom-up estimation
• Operations — Process mapping + bottleneck identification + optimization

PEI (Personal Experience Interview)

McKinsey's PEI evaluates three dimensions with deep-dive STAR stories:

1. Personal Impact — "Tell me about a time you created significant change"
2. Entrepreneurial Drive — "Tell me about building something from nothing"
3. Inclusive Leadership — "Tell me about leading a diverse team through a challenge"

Prepare 2 stories per dimension. Each should be 5-8 minutes with deep follow-up readiness. Practice with AI-powered behavioral practice.

Also Relevant

See our general consulting interview guide for BCG and Bain preparation.