TAM/SAM/SOM Calculator
Calculate Total Addressable Market, Serviceable Available Market, and Serviceable Obtainable Market with explicit assumptions, citations, and 1-3 year projections — defensible market sizing for investors, execs, and PMF validation.
Your pitch deck says "$50B market" with no source — and the first investor question torpedoes the meeting. Market size without citations is just a guess wearing a tuxedo. The cure is TAM-SAM-SOM with population counts, real data sources (Census, IBISWorld, Statista), and a SOM that's 1-15% of SAM, not 100%.
Who it's for: PMs preparing investor decks, founders sizing markets pre-seed/Series A, exec teams validating new product lines, BizOps leads building business cases
Example
"Size the market for a SmartInvoice tool for US freelancers" → TAM: 60M freelancers × $300 ARPA = $18B → SAM: 12M with active client billing × $300 = $3.6B → SOM: 5% in Year 3 = $180M, 600K customers — with Census/BLS/Statista citations and competition assumptions
CLAUDE.md Template
New here? 3-minute setup guide → | Already set up? Copy the template below.
npx ccplaybooks add tam-sam-som-calculator# TAM/SAM/SOM Calculator
Calculate Total Addressable Market (TAM), Serviceable Available Market (SAM), and Serviceable Obtainable Market (SOM) with explicit assumptions, citations, and caveats. Use when sizing a market for an idea, business case, or executive review.
Not a back-of-napkin guess — a structured, citation-backed analysis that withstands scrutiny.
## The Three-Tier Model
- **TAM** — Total demand if you captured 100% of the market
- **SAM** — TAM segment you can realistically target (geography, firmographics, product fit)
- **SOM** — Portion of SAM you can capture in 1-3 years (competition, GTM constraints)
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What This Does
Walks through 4 adaptive questions (problem space → geography → industry segment → customer profile) then generates a citation-backed TAM/SAM/SOM analysis with population estimates, market size calculations, and 1-3 year SOM projections. Includes optional Python helper script for deterministic math.
Pairs with positioning-statement, problem-statement, and recommendation-canvas.
Quick Start
mkdir -p ~/Documents/MarketSizing
mv ~/Downloads/CLAUDE.md ~/Documents/MarketSizing/
cd ~/Documents/MarketSizing
claude
Provide product context (your website copy, or a competitor analog) plus geography. Claude asks 4 adaptive questions and produces a citation-backed analysis.
The Three Tiers
| Tier | Definition | Typical Range |
|---|---|---|
| TAM | If you captured 100% of demand | Total industry size |
| SAM | Realistically targetable segment | 5-30% of TAM |
| SOM | Capturable in 1-3 years | 1-15% of SAM |
Tips & Best Practices
- Cite every number. Census, BLS, IBISWorld, Statista, Gartner — with URLs.
- Population AND dollars. "$1.2B" without "60K customers" can't drive a sales plan.
- SOM ≠ SAM. A SOM that equals SAM is a tell that you skipped competition analysis.
- Ground SOM in GTM capacity. "50% Year 1" with no sales team is fiction.
- Reassess annually. Markets shift; old TAM/SAM/SOM rots.
Common Pitfalls
- TAM without citations ("the market is huge")
- SOM = SAM (assumes 100% capture, zero competition)
- Only dollars, no customer counts
- Static numbers from 3 years ago
- SOM that ignores sales/marketing capacity