Quick Reference for Estimation Questions
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For PM estimation questions, it’s useful to develop a bit of intuition about numbers, and to memorize a few key ones. Here’s a list that we recommend PM interviewees be familiar with.
Please keep in mind. This fact sheet is NOT meant to be memorized. Use this guide to get a general sense of numbers and sizes. This fact sheet is intentionally brief, since many PM interviewees often mistakenly spend wasted hours memorizing numbers, when it's rarely relevant for the interview.
Figures are updated as of Q2 2025.
- US population: 341M
- California population: 40M
- NYC population: 8.5M
- World population: 8.2B
- Size of continental US: 3M square miles
- US households: 130M
- Average people per household in the US: 3
- Life expectancy: 72
- Median household income: $81,000
- Weight of an average car: 4000lbs
Technical
- Amazon S3 Standard cost: $0.023 / GB / month
- Average file size for a 90-min 720p movie: roughly 1.5GB
- Average file size for a smartphone camera picture: roughly 3-9 MB
- Average CTR for a Google search ad: 5%
- Average landing page conversion rate: 4%
- Average WiFi bandwidth: 280Mbps
- Cost of iPhone 17 Pro: $1099
- Cost of Google Pixel 9: $799
General sense of revenue (from 2024)
- Dropbox revenue: $2.5B
- Airbnb revenue: $15B
- Google revenue: $350B
- Meta revenue: $164B
- Apple revenue: $538B
- Amazon revenue: $867B
- Netflix revenue: $53B
- Google (Alphabet) net income: $100 billion
- Apple R&D expenditure: $31 billion
General sense of user populations
- Netflix (Q1 2025): 300M subscribers
- Google G Suite (Q1 2025): 2.5B monthly active users
- Uber (Q2 2025): ~8.8M drivers worldwide
- Twitter (Q2 2025): 250M daily active users
- Number of Americans that own a smart speaker (2025): 35% of adults
- Number of products Amazon sells (2024): over 12 million (not including Amazon marketplace sellers, which brings the total to 400 million)