Article · ~12 min read

Market Size: What is TAM, SAM, & SOM?

Carta · carta.com Free Intermediate

A clear, no-nonsense primer on the three market-size numbers every founder gets asked about, with the bottom-up method that actually holds up in front of investors. Pick this over the SEO listicles because it comes from a platform that lives inside real cap tables and fundraises.

  • TAM is the whole category, SAM is what you can realistically serve, SOM is what you can win near-term.
  • Build the numbers bottom-up (customers times price), not top-down percentages of a giant number.
  • A defensible SOM matters more to investors than an impressive TAM slide.
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The question it answers

  1. What are TAM, SAM, and SOM and how do I actually calculate them?

Read with it

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  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. A concrete, copyable Google Sheet (no paywall, no credit card) that builds your number bottoms-up from customer segments and... Visible.vc Template · ~15 min to fill in Total Addressable Market Template (free Google Sheet) Mike Preuss
  5. This lays out both the top-down (start from a big industry number) and bottom-up (build up from your own price times likely... HubSpot Blog Article · ~12 min read TAM, SAM & SOM: What Do They Mean & How Do You Calculate Them? Clifford Chi
  6. Blume's annual report is the single best data-grounded read on what is actually happening in Indian internet and consumption,... Blume Ventures Article · ~180 charts Indus Valley Annual Report 2025 Sajith Pai, Anurag Pagaria and team (Blume Ventures)
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