← Google Interview Insights

Google·Product Manager·Onsite - Product Sense / Strategy·Intermediate

Intermediate
Jun 2026

Summary

Google PM interview with a market sizing question about grocery stores in a city. Pretty standard estimation exercise but it made me realize how rusty I was on structuring these things under pressure.

Questions Asked (1)

Q1

How many grocery stores would a large metropolitan city need?

Product Analytics & MetricsProduct Sense & Ideation
Author's notes

I jumped straight into population numbers without pausing to define what 'need' even means, which felt sloppy in retrospect.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Clarify the scope by defining the city's population and assuming a standard grocery store size and shopping frequency. Then estimate demand based on household grocery needs and supply based on store capacity, and reconcile the two to determine the number of stores needed.

Pro tip: Acknowledge that grocery stores vary in size and format (e.g., supermarkets, convenience stores) and that competition and geography affect distribution; state your assumptions clearly and offer to adjust if needed.

1. Clarify scope and assumptions

Ask clarifying questions to define the city's population, average household size, and what constitutes a 'grocery store' (e.g., full-service supermarket). State any assumptions you make.

2. Estimate demand

Calculate total weekly grocery spending or volume by multiplying the number of households by average weekly grocery needs. This represents the total demand the city must satisfy.

3. Estimate supply per store

Determine the average capacity of a grocery store in terms of revenue or customers served per week, based on typical store size and throughput.

4. Calculate number of stores

Divide total demand by the capacity per store to get a baseline number. Adjust for factors like competition, geography, and shopping preferences.

5. Sanity check and refine

Compare your estimate to known benchmarks (e.g., stores per capita in similar cities) and discuss potential variations due to income levels, car ownership, and online grocery penetration.

Key Points to Mention

  • Population and household size assumptions
  • Average grocery spending per household per week
  • Store capacity in terms of revenue or customers
  • Market saturation and competition
  • Geographic distribution and accessibility
  • Impact of online grocery and alternative formats

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.