The 8 Most Important Case Math Concepts for MBB Consulting Interviews

If you’re aiming for McKinsey, BCG, or Bain, mastering case math is non-negotiable. Beyond frameworks and creativity, your ability to quantify impact sets you apart. Below are the eight most important case math concepts every MBB candidate must understand — explained simply, without formulas.

For the exact equations, real industry examples, and step-by-step methods, explore the full Case Math Handbook, designed to help you calculate like a consultant under pressure.

1. Profitability Analysis

The foundation of nearly every case. Profitability analysis breaks down how revenue and cost drivers interact to affect the bottom line. You’ll learn to decompose profits into logical buckets, identify where issues stem from, and quantify the magnitude of impact. It’s the single most tested skill in consulting interviews.

2. Weighted Average Calculations

Real businesses rarely have just one product, customer, or channel. Weighted averages help you combine multiple performance metrics — like margins or prices — into one meaningful measure. This concept shows you can handle real-world complexity and avoid oversimplified math that leads to wrong conclusions.

3. Break-even Analysis

Used to determine when revenues cover costs, this analysis reveals the minimum volume or price needed for profitability. Interviewers love it because it blends both logic and math: you’re proving whether a proposed idea is financially viable. It’s essential for pricing, investment, and operations cases alike.

4. Market Sizing

The ultimate test of structured thinking. Market sizing asks you to estimate market potential using logic, segmentation, and reasonable assumptions. Whether you go top-down or bottom-up, it’s not about being exact — it’s about being clear, methodical, and realistic in your reasoning.

5. ROI Investment Evaluation

Return on Investment is how consultants think about efficiency — whether an initiative creates value relative to its cost. In interviews, you’ll use ROI to evaluate capital projects, marketing campaigns, or product launches. Understanding how to interpret ROI over time separates candidates who can calculate from those who can recommend.

6. Funnel Conversion

Every customer journey has drop-offs, and great candidates quantify them. Funnel math helps you analyze where users fall out of a process — from awareness to purchase — and identify the biggest opportunities to improve conversion. It’s critical for marketing, sales, and digital platform cases.

7. Market Share

A simple but powerful metric that signals competitive position. Market share questions test whether you can connect percentages to real-world outcomes: pricing power, brand strength, and customer loyalty. Top candidates don’t just compute share — they interpret what shifts in share actually mean.

8. Customer Lifetime Value (CLV)

CLV combines acquisition cost, retention, and margin into one metric of long-term profitability. It’s central to subscription, SaaS, and consumer business cases. Understanding CLV demonstrates your ability to link marketing and financial strategy — a hallmark of real consulting judgment.

Go From Concepts to Consultant-Level Mastery

Each of these eight concepts has clear formulas, solved examples, and detailed explanations inside the Case Math Handbook. You’ll see how consultants apply them across industries — from airlines to tech to retail — and learn how to communicate your math like an MBB interviewer expects.