Template · ~15 min to fill in

Total Addressable Market Template (free Google Sheet)

Mike Preuss · Visible.vc Free Intermediate

A concrete, copyable Google Sheet (no paywall, no credit card) that builds your number bottoms-up from customer segments and price, then runs a sensitivity analysis on penetration. Since your instinct was already bottoms-up, this gives you a clean, defensible artifact to actually show instead of a slide with one round number. It also frames SAM and SOM off the same build, so the whole market slide stays internally consistent.

  • Build TAM by segment (for example SMB, mid-market, enterprise), each with its own count and price, so the total is a sum of assumptions you can defend line by line.
  • The sensitivity table shows revenue across different penetration rates, which reframes the conversation from a single big number to a realistic range you can capture.
  • Copy the sheet to your own Drive and swap in your real numbers; it is a working model, not a static PowerPoint, so an investor can interrogate the inputs live.
Open on visible.vc ↗

It answers 4 questions

  1. How big does my market need to be for this to be a real business?
  2. What are TAM, SAM, and SOM and how do I actually calculate them?
  3. How do I estimate a market size when the product I'm building doesn't have a category yet?
  4. How much of the market do I realistically need to capture for this to be a real business?

Read with it

  1. The single best thing ever written on customer conversations. It teaches you to ask about the customer's life and past... momtestbook.com Book · ~130 pages The Mom Test Rob Fitzpatrick
  2. Most market sizing advice online is generic TAM SAM SOM filler. This one is written by an investor, backed by a survey of 30... Pear VC Essay · ~15 min read Market Sizing Guide Ian Taylor
  3. When there is no category report to point at, you have to build the number yourself, and this is the essay that teaches you... Andreessen Horowitz Essay · ~20 min read 16 More Startup Metrics Anu Hariharan, Frank Chen, Jeff Jordan
  4. Video · ~50 min How to Evaluate Startup Ideas Kevin Hale, Y Combinator
  5. Before you sweat which side to seed, Gurley helps you judge whether your marketplace is even structurally worth building. He... Above the Crowd Essay · 20 min read All Markets Are Not Created Equal: 10 Factors to Consider When Evaluating Digital Marketplaces Bill Gurley
  6. The definitive essay on where good ideas come from: notice problems you personally have, don't force it. Use it as the lens for... paulgraham.com Essay · ~20 min read How to Get Startup Ideas Paul Graham
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