What Is TAM, SAM, SOM? #
TAM, SAM, and SOM are three concentric layers of market sizing — each narrowing the lens from the total theoretical opportunity to what your business can realistically capture.
| Layer | Full Name | Question It Answers |
|---|---|---|
| TAM | Total Addressable Market | How big is the entire market if you captured 100%? |
| SAM | Serviceable Addressable Market | How much of that market can you actually serve (geography, segment, capability)? |
| SOM | Serviceable Obtainable Market | How much can you realistically capture in the near term? |
The framework is used in business plans, investor pitches, market entry analysis, and strategic planning. Federal data from Census Bureau SUSB provides the TAM (total industry revenue by NAICS code). Geographic and segment-level data from Census CBP narrows to SAM. Competitive analysis from establishment counts and SEC EDGAR data informs the SOM estimate.
How to Calculate TAM, SAM, and SOM #
Bottom-up: Start with your unit economics (price × potential customers) and scale up.
TAM Calculation:
Total industry revenue for your NAICS code from Census SUSB. For US restaurants (NAICS 72251), TAM is the total receipts for all eating places nationally. This is the broadest defensible number.
SAM Calculation:
Narrow TAM by the segments you can actually serve. If you operate full-service restaurants in three states, your SAM is the Census CBP revenue for NAICS 722511 in those three states — not the national figure. Geographic and format filters convert TAM to SAM.
SOM Calculation:
Your realistic capture within SAM, typically based on your current market share trajectory, establishment count relative to total, and competitive position. If there are 5,000 restaurants in your SAM geography and you operate 10, your current SOM is approximately 0.2% of SAM — and your growth plan should explain how and why that percentage increases.
Want the full what is tam sam som data?
Complete data with 5-year forecasts, geographic breakdowns, and competitive analysis. Every data point sourced and cited.
TAM SAM SOM Examples #
Example: A Regional Restaurant Chain
| Layer | Scope | Data Source |
|---|---|---|
| TAM | All US full-service restaurants (NAICS 722511) | Census SUSB total receipts |
| SAM | Full-service restaurants in target 3-state region | Census CBP state-level data |
| SOM | Realistic capture based on 10 locations, planned expansion to 25 | Current revenue ÷ SAM, growth plan |
Example: A B2B Software Company
| Layer | Scope | Data Source |
|---|---|---|
| TAM | All US businesses in target NAICS codes × average software spend | Census CBP establishment counts × pricing |
| SAM | Businesses with 50+ employees in target verticals | Census SUSB firm size distribution |
| SOM | Realistic customer acquisition over 3 years based on sales capacity | Bottom-up: pipeline × conversion rate × ACV |
Common Mistakes and Best Practices #
| Mistake | Fix |
|---|---|
| Presenting TAM as the opportunity | Always show SAM and SOM — TAM is context, not strategy |
| Using third-party estimates without verification | Cross-check against Census SUSB/CBP — federal data is the most defensible source |
| SOM without a credible capture mechanism | Back SOM with unit economics: locations × revenue per location, or customers × ACV |
| Static market sizing | Apply industry CAGR to project future TAM — show the market is growing or declining |