What market sizing examples is really testing
Market-sizing examples teach how the same core method adapts to consumer demand, business demand, physical capacity, and transaction flows.
The published answer is not the target. A different number can be equally strong when the equation is coherent and the assumptions are transparent.
A step-by-step method for market sizing examples
For each example, pause after the prompt, define the market, write two possible estimation routes, and select one. Review where the solution made a different modeling choice and whether it is more defensible.
Define what counts
Specify buyer, product, geography, period, channel, and output unit.
Sketch two routes
Write a demand-side and supply-side equation before choosing.
Choose anchor assumptions
Use explainable numbers and identify which assumption dominates.
Calculate a range
Use round numbers and sensitivity where uncertainty is material.
Cross-check independently
Use per-capita spend, outlet throughput, capacity, or an adjacent market.
Worked example: market sizing examples
Follow the reasoning, then rebuild it for a different industry instead of memorizing the wording.
What good looks like
- The market definition is explicit.
- The model has one clear unit flow.
- Assumptions have anchors or ranges.
- An independent method lands in the same order of magnitude.
Additional market sizing examples to attempt
The prompts below deliberately require different model shapes. Define the unit before deciding which facts you need.
Do not look for a canonical answer. Write the equation, assumptions, and cross-check that make your estimate defensible.
- Annual revenue from airport lounge visits in a major region.
- Number of commercial kitchen inspections required in a city each year.
- Market for replacement batteries for delivery e-bikes.
- Daily transactions processed by independent pharmacies.
- Number of data-center technicians required nationally by 2030.
Mistakes to avoid
- Copying assumptions from another country without calibration.
- Adding segments that do not change behavior.
- Using circular cross-checks with the same assumptions.
- Reporting a precise point estimate despite wide uncertainty.
How to practice deliberately
Solve one consumer-spend, one B2B, one capacity, and one transaction prompt.
Use both top-down and bottom-up on at least one prompt.
Vary the dominant assumption by ±20% and observe the output.
Deliver the final range, sensitivity, and business implication in 30 seconds.
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Frequently asked questions
Are there correct answers to market sizing examples?
There may be real-world data, but interviews primarily evaluate the model, assumptions, math, and interpretation. Several estimates can be defensible.
Should I use top-down or bottom-up?
Choose the route with more reliable anchors and a cleaner connection to the requested quantity. Use the other route as a cross-check when practical.
How detailed should segmentation be?
Segment only where behavior or economics differ enough to change the estimate. Extra detail is not automatically more accurate.
Sources and further reading
- Interviewing at McKinsey: McKinsey & CompanyPrimary source for McKinsey recruiting and interview guidance.
- Consulting interview process: Boston Consulting GroupPrimary source for BCG interview stages and evaluated capabilities.
- Interviewing at Bain: Bain & CompanyPrimary source for Bain case-interview expectations and sample cases.