Market Sizing Questions, Examples & Answers for Case Interviews

10 market sizing questions to practice

Estimate the annual U.S. market for coffee shop drinks.
Estimate the number of electric vehicle chargers needed in Chicago.
Estimate the market for home fitness subscriptions in the U.S.
Estimate annual revenue for airport parking at a major airport.
Estimate the market size for premium dog food in New York City.
Estimate how many rideshare trips happen in Los Angeles each day.
Estimate annual sales of running shoes in the U.S.
Estimate the market for corporate meal delivery in Boston.
Estimate the number of hotel rooms needed for a large convention.
Estimate annual spending on streaming services by college students.

Answer structure

Use a simple structure: define the market, choose top-down or bottom-up, segment the population, estimate usage, apply price or spend, then sanity check. For a coffee shop market, you might estimate urban adults, visits per week, drinks per visit, and average price.

End with a takeaway. A market size by itself is not the answer; the client needs to know whether the opportunity is big enough, attractive enough, or worth further research.

Worked example: coffee shop drinks

Question: Estimate annual U.S. coffee shop drink revenue. There is not one perfect answer; the point is to choose a clear structure, make reasonable assumptions, keep units visible, and sanity check the range.

Answer 1: customer approach

Use adults x coffee-shop buyers x visits x price. If the U.S. has roughly 260 million adults, 50% buy coffee-shop drinks, and each buyer averages two visits per week at $5 per drink, annual revenue is 260 million x 50% x 2 x 52 x $5, or about $67.6 billion.

Answer 2: store approach

Use coffee shops x drinks per day x price x days. If there are roughly 40,000 coffee shops, each sells 500 drinks per day, and the average drink is $5, annual revenue is 40,000 x 500 x $5 x 365, or about $36.5 billion.

The exact number can vary. The stronger answer is the logic: clear scope, simple assumptions, visible units, and a final comment that the market is large but fragmented, so a new entrant would still need a differentiated location, format, or brand.

Should I memorize market sizing answers?

No. Memorize the process, not the numbers. Interviewers are testing your reasoning under ambiguity.

What if my assumptions are wrong?

Use reasonable round numbers and state them clearly. A defensible assumption is usually enough if your structure and math are coherent.

Example answers for the 10 practice problems

1. U.S. coffee shop drinks: customer approach

Use 260 million adults x 50% coffee-shop buyers x 2 drinks per week x 52 weeks x $5 per drink = about $68 billion per year. Takeaway: the market is very large, but success depends on location density, brand, convenience, and repeat purchase.

1. U.S. coffee shop drinks: store approach

Use roughly 40,000 coffee shops x 500 drinks per day x $5 x 365 days = about $37 billion per year. This lower answer may exclude convenience stores and restaurant coffee, so the range could be $40-70 billion depending on scope.

2. EV chargers in Chicago

Assume Chicago has 1.1 million cars, 10% are EVs over time, and each public charger can support about 20 active EVs. That implies 110,000 EVs / 20 = 5,500 public chargers. The answer should then be adjusted for home charging, commuting patterns, and downtown parking density.

3. Home fitness subscriptions

Start with 130 million U.S. households. If 30% are fitness-interested and 20% of those pay for home fitness, that is 7.8 million subscribing households. At $20 per month, annual spend is 7.8 million x $240 = about $1.9 billion.

4. Airport parking revenue

Assume a major airport has 30,000 parking spaces, 75% average utilization, and $25 average daily revenue per occupied space. Annual revenue is 30,000 x 75% x $25 x 365 = about $205 million. The key driver is utilization during peak travel periods.

5. Premium dog food in NYC

Assume NYC has 3.2 million households, 20% own dogs, and 35% of dog owners buy premium food. That is 224,000 premium dog-food households. At $900 annual spend per dog household, the market is about $200 million per year.

6. LA rideshare trips per day

Assume 10 million people in LA County, 20% use rideshare monthly, and each active user takes 4 trips per month. Monthly trips are 10 million x 20% x 4 = 8 million, or about 267,000 trips per day. Tourism and airport trips could push the estimate higher.

7. U.S. running shoe sales

Assume 260 million adults, 30% buy running or athletic training shoes annually, and average spend is $100. Annual market size is 260 million x 30% x $100 = $7.8 billion. The market gets larger if kids, casual athletic wear, and multiple pairs per year are included.

8. Corporate meal delivery in Boston

Assume 600,000 office workers, 20% work in companies that regularly order meals, and those employees receive 2 delivered meals per month at $18. Annual spend is 600,000 x 20% x 2 x 12 x $18 = about $52 million.

9. Hotel rooms for a convention

Assume 50,000 attendees, 70% travel from out of town, 1.4 attendees per room, and 3 nights per visitor. Rooms needed per night are 50,000 x 70% / 1.4 = 25,000 rooms. Total room nights are 25,000 x 3 = 75,000.

10. Streaming by college students

Assume 19 million college students, 80% pay for at least one streaming service, and average spend is $12 per month after student discounts and sharing. Annual spend is 19 million x 80% x $12 x 12 = about $2.2 billion.

How to answer market sizing questions

Start by clarifying the market definition, geography, customer, and timeframe. Then choose a top-down or bottom-up structure, state each assumption before using it, keep units visible, and sanity check the answer. Finish with what the estimate means for the client.

Use the market sizing questions examples on this page to practice both the setup and the spoken explanation, not just the arithmetic.

Market sizing example structure

For consumer markets, use population times target share times purchase frequency times price. For capacity markets, use locations or assets times utilization times price.

Market sizing exercises

Practice by estimating one market per day, then compare whether your answer was directionally reasonable. The goal is repeatable logic, not a memorized number.

PDF-style practice list

If you want a market sizing questions PDF-style workflow, copy the 10 prompts above into a document and write one-page answer notes for each: structure, assumptions, math, and takeaway.

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