For management consultants
Consulting Interview Help — AI for Case Interviews, PEI & Math Drills
Free real-time AI for consulting interviews at McKinsey, BCG, Bain, and the Big 4. Profitability cases, market sizing, M&A, market entry, the McKinsey PEI, and timed math drills. Permanent free tier, screen-share-safe on Zoom, Teams, Google Meet, and HireVue.
The 3 round types in every MBB loop
McKinsey, BCG, and Bain loops vary in cultural emphasis but cover the same three round types. CoPilot Interview surfaces the right framework prompts per round.
1. Case interview (profitability, market sizing, M&A, market entry)
The signature round. You will be given a business problem — "client's profits are down 20%, why?" or "should our client acquire X?" or "estimate the US market for pet insurance" — and graded on structure, hypothesis-driven thinking, MECE decomposition, and quantitative agility. CoPilot Interview surfaces the appropriate framework as you talk: the profitability tree (revenue × price × quantity; cost = fixed + variable), 4Ps for market entry, Porter's 5 Forces for competitive analysis, and NPV / breakeven for go/no-go decisions.
2. Personal Experience Interview (PEI / fit)
McKinsey calls it PEI and weights it heavily. Bain calls it the "personal experience" round. BCG runs it as part of the broader fit screen. Three stock prompts you will see: tell me about leadership without authority, tell me about resolving disagreement, tell me about persisting through difficulty. The AI surfaces STAR+ structure (Situation, Task, Action, Result, Reflection) and flags missing quantification. Consulting interviewers are especially strict on concrete numbers: "we improved retention 14 points" beats "we improved retention."
3. Timed math drill & data interpretation
Most loops include a math screen: percentages, breakeven, NPV, growth calculations under time pressure. The classic question is "if revenue grew 15% per year for 5 years, what's the cumulative growth?" The AI prompts the shortcut (rule of 72 for doubling time, exact compound formula for non-trivial cases) without doing the math for you — the interviewer watches your reasoning, not just your number.
Case frameworks the AI surfaces automatically
| Framework | Used for | Quick check |
|---|---|---|
| Profitability tree | "Profits are down" cases | Revenue − Cost. Revenue = Price × Quantity. Cost = Fixed + Variable. Decompose only the branch that explains the change. |
| 4Ps | Marketing / market entry | Product, Price, Place, Promotion. Best for product launches. |
| Porter's 5 Forces | Industry attractiveness | Buyer power, Supplier power, Substitutes, New entrants, Rivalry. |
| M&A framework | "Should client acquire X?" | Standalone value, Synergies (revenue + cost), Strategic fit, Risks (cultural, regulatory, integration). |
| MECE | Any structure validation | Mutually Exclusive, Collectively Exhaustive. Apply to every tree before continuing. |
| 2×2 matrix | Prioritization / segmentation | High/low on two axes (impact vs effort, value vs cost, attractiveness vs feasibility). |
How firms differ in what they weight
McKinsey
Heavy on structure and synthesis. PEI is uniquely weighted: usually one full 30-minute round dedicated to personal experience. Interviewers want explicit framework naming. The "Imbellus" digital assessment (problem-solving game) screens before live rounds.
BCG
Creative problem decomposition matters more than at McKinsey. The "BCG Potential Test" (online assessment) is the gating step. Cases often have less structured prompts; you are expected to define the question scope yourself.
Bain
Cultural warmth and energy are explicitly weighted. The PEI is called the "personal experience" round. Bain interviewers are looking for someone they want to spend 80 hours a week with. Smile, engage, and make the case feel collaborative.
Big 4 (Deloitte Monitor, Strategy&, EY-Parthenon, KPMG)
Generally less rigid than MBB on framework discipline. Cases may be more industry-specific. Cultural fit screens are heavier. Pay and lifestyle expectations are different so the "why this firm" answer matters more.
Tier 2 (Oliver Wyman, AT Kearney, ZS, Roland Berger)
Cases at Oliver Wyman are notoriously quantitative. AT Kearney leans operational. Each firm has a distinct case style; review three sample cases from each firm before applying.
Why CoPilot Interview fits consulting specifically
Consulting interviews are structured talking under pressure — very different from coding interviews where you sit and type. The AI assistance has to be glanceable, not pulling-your-attention-away. CoPilot Interview's Ghost Mode overlay surfaces a one-line framework prompt during pauses; you read it and keep talking. The model choice matters here: Claude reasons through complex hypothesis trees better than Llama; for senior-level cases at MBB final rounds, the premium tier is worth the upgrade.
The other practical reason: consulting interviewers run multiple rounds back-to-back. By round 4 of a final-round day, you're tired. Having structured prompts in front of you preserves clarity when fatigue starts hurting framework discipline.
Permanent free tier vs the 10-minute trial elsewhere
Most AI interview tools targeting consulting (including Final Round AI) offer a 10-minute trial of the live Copilot before requiring payment. That's less than one practice case. CoPilot Interview's free tier is permanent: no time limit, no credit card. Free models (Llama, Qwen) respond in 3-5 seconds and handle most regular-round cases. For final-round practice at MBB, the Standard plan ($8.99/mo) adds premium models — still less than a single hour with a human coach.
FAQ
Yes. CoPilot Interview's real-time AI handles the three primary consulting interview round types: the case interview (profitability, market sizing, M&A, market entry), the personal experience interview, and the math / data interpretation drill. It works on Zoom, Teams, Google Meet, and HireVue, and includes frameworks like MECE, the profitability tree, and hypothesis-driven structure prompts.
MBB (McKinsey, BCG, Bain), Big 4 strategy practices, Tier 2 firms (Oliver Wyman, AT Kearney, ZS), and boutiques. The frameworks are universal; what changes is the cultural emphasis.
MECE stands for Mutually Exclusive, Collectively Exhaustive. It is the structural standard for any answer in a case interview — your decomposition must cover all possibilities without overlapping. Interviewers grade explicitly on whether your structure is MECE.
Adequate for first-round cases. For final rounds (especially McKinsey, BCG, Bain), the premium models (Claude, GPT) handle the harder hypothesis-driven cases better. The free Llama/Qwen models respond in 3-5 seconds and are sufficient for practice and most regular-round cases.
Most consulting firms have not formally addressed AI assistance in interviews. The frameworks the AI surfaces (MECE, profitability tree, 4Ps) are public knowledge already — using them is not deception. Always follow whatever rules the firm has stated. See our manifesto on how we think about this.
Try the free tier on your next case practice
Permanent free tier, no credit card. Windows and macOS. Surfaces framework prompts at the moment you need them, without pulling attention from the case.
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