Learn the case interview basics, practice with 200+ cases, and benefit from extensive test materials, and interactive self-study tools.
Topic Overview
Topic Overview
Getting Started
Learn how to prepare for your case interview in a structured and efficient way, and maximize your chances of success.
Preparation Plan
Self Study
Practice With Peers
Practice with Coaches
Learn all about the different types of cases in consulting interviews and how to be well-prepared for every challenge.
Market Sizing
Market Entry
Brainteaser
Growth Strategy
M&A Cases
Pricing
Competitive Response
Valuation
Profitability Cases
Structuring
Understand why a clear structure is crucial in case interviews and how it helps you solve complex cases efficiently.
Approaching a Case
How to Build a Good Structure
How to Communicate Your Structure
How to Practice Structure
Math in Case Interviews
Learn about the most common mathematical requirements in case interviews and how to handle them confidently and efficiently.
Why Math Matters
Fast Math
How to Practice Math Skills
Business Concepts
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Important Facts

In case interviews, having solid general knowledge can make a big difference, especially in market sizing questions. Knowing basic facts about regions, population sizes, and economic indicators helps you build stronger arguments. It’s not just about the analysis itself but also about showing interviewers that you understand global trends and can quickly process key information — an important skill in consulting.

In a case interview, quick and accurate estimates are essential. For example, if you're asked to evaluate the potential market for a product in a specific country, having solid data — like the population size — is crucial. Without this information, it can be challenging to make a meaningful calculation.

In addition to national market data, it's important to know about key global markets. Being familiar with major economic regions like the U.S., China, and the EU is valuable because large consulting firms such as McKinsey and BCG operate extensively in these areas. A solid understanding of these regions shows that you can think about global factors and helps you stand out from other candidates.

What Your Knowledge of Population, Economy & Geography Says About You

Having strong general knowledge in specific areas not only shows that you are well-prepared, but also that you can quickly understand economic relationships—a crucial skill in consulting. When you have information like population sizes or a country's Gross Domestic Product (GDP) at your fingertips, you can quickly verify assumptions and make informed decisions, which is exactly what case interviews expect.

Additionally, your knowledge of these topics demonstrates a genuine interest in world affairs and your ability to recognize and understand global trends. This insight is vital for evaluating how political, economic, and social changes affect businesses. It also highlights your capability to absorb and use complex data effectively.

Population

Country/RegionPopulation (approx.)
Worldwide8.05 billion
China1.426 billion
India1.419 billion
Europe746 million
USA335 million
Indonesia277 million
Brazil203 million
Russia143 million
Japan124 million
Germany83 million
UK68 million

GDP Forecast in USD for 2024

Country/RegionGDP 2024 (approx. in billions USD)
Worldwide105 billion USD
USA25 billion USD
China18 billion USD
Japan4.3 billion USD
Germany4.5 billion USD
France3.0 billion USD
UK3.1 billion USD
India3.9 billion USD
Italy2.2 billion USD
Brazil2.1 billion USD
Canada2.2 billion USD

Key Data to Know for Your Case Interview

In case interviews, making quick and accurate estimates is key. A good grasp of units, along with basic fraction and percentage calculations, is essential for working efficiently. Additionally, being comfortable with time units is important for making rough estimates and calculations. The table of larger and smaller time units below provides a handy overview of commonly needed values. These fundamental skills help you tackle tasks confidently and quickly.

Overview of Time Conversions: Days, Weeks and Hours

Larger UnitsSmaller Units
Days/Year365 days (In leap years: 366 days)
Days/3 Years1,095 days
Days/4 Years1,461 days (including 1 leap year)
Weeks/Year52 weeks
Hours/Week168 hours
Seconds/Hour3,600 seconds

Conversion of Fractions to Percentages and Decimal Values

FractionPercentageDecimal
1/520%0.20
1/616.67%0.1667
1/714.29%0.1429
1/812.5%0.125
1/911.11%0.1111
1/1010%0.10
1/119.09%0.0909
1/128.33%0.0833
1/137.69%0.0769
1/147.14%0.0714
1/156.67%0.0667
1/166.25%0.0625
1/175.88%0.0588
1/185.56%0.0556
1/195.26%0.0526
1/205%0.05

Remember, it’s not enough to just memorize these numbers—you also need to be able to calculate with them effectively!

👉 Use our Mental Math Tool to specifically train your math skills and prepare for your next interview.

👉 Our Math and Formulas Guide helps you understand key economic and financial concepts, allowing you to apply them effectively in interviews!

Conclusion: General Knowledge as the Foundation for a Successful Interview

A strong general knowledge base is essential for a successful case interview. It not only helps you make accurate market estimates but also demonstrates your understanding of global economic connections. Whether it’s population figures, economic data, or basic geographic knowledge, having these facts at your fingertips allows you to approach the interview with confidence. Familiarity with mathematical data and time units is also crucial in case interviews. So, prepare thoroughly, leverage your knowledge effectively, and set yourself apart from the competition!

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