McKinsey Interview Guide — Case & PEI Mastery 2026

McKinsey interviews combine Case Interviews (structured problem-solving) with the Personal Experience Interview (PEI). Cases test your analytical and structured thinking. PEI probes leadership, personal impact, and entrepreneurial drive using deep behavioral questions.

Interview Process

McKinsey's process: (1) Resume screen and online assessment (PST or Solve game), (2) First round — 2 interviews (1 case + 1 PEI each), (3) Final round — 3 interviews (same format, senior partners). Each interview is ~40 minutes: ~15 min PEI + ~25 min case. The bar is extremely high at every stage.

The Case Interview

Case interviews present a business problem (e.g., "Should this airline launch a low-cost carrier?"). You must: clarify the problem, propose a structured framework, analyze data provided, synthesize findings, and deliver a recommendation. McKinsey expects top-down communication — state your answer first, then support it.

The PEI (Personal Experience Interview)

PEI evaluates three dimensions: (1) Personal Impact — a time you influenced others without authority, (2) Entrepreneurial Drive — a time you created something from nothing or drove change, (3) Leadership — a time you led a team through a challenge. Prepare 2-3 detailed stories for each. McKinsey probes deeply — expect 10+ follow-up questions per story.

Preparation Strategy

For cases: practice 30-50 cases using frameworks (profitability, market entry, pricing). Master mental math. Practice top-down communication. For PEI: prepare 6-9 deeply detailed stories. Practice telling each story in 2 minutes, then be ready for 10 minutes of follow-ups. McKinsey values "obligation to dissent" — show you speak up when you disagree.

Key Tips

  • •State your hypothesis upfront in cases — McKinsey values top-down communication.
  • •For PEI, prepare stories with extreme depth — expect 10+ follow-up questions.
  • •Practice mental math: percentages, market sizing, compound growth.
  • •Show "obligation to dissent" — times you respectfully pushed back.
  • •Structure is king — always lay out your approach before diving into analysis.

Frequently Asked Questions

How many cases should I practice?

30-50 cases minimum. Focus on quality over quantity — debrief each case to understand what you could improve. Practice with partners who can give real-time feedback.

What is the McKinsey Solve game?

McKinsey replaced the Problem Solving Test (PST) with an online assessment called "Solve." It includes ecosystem-building and pattern-matching games that evaluate problem-solving, decision-making, and systems thinking.

Related Resources

How to Interview at Google — Complete Guide 2026

Master the Google interview process with insider tips on Googleyness, structured interviews, and what hiring committees look for.

Amazon Interview Guide — Leadership Principles Mastery 2026

Ace the Amazon interview by mastering the 16 Leadership Principles with STAR-format answers, bar raiser tips, and LP-specific preparation.

How to Interview at Meta — Complete Guide 2026

Prepare for Meta interviews with tips on demonstrating impact, moving fast, and navigating the behavioral and technical rounds.

Practice for This Company

Start a mock interview tailored to this company's culture and interview style.

Start Practice InterviewBrowse All Resources