TAM SAM SOM is a market-sizing framework – Total Addressable Market, Serviceable Available Market, and Serviceable Obtainable Market – originally used for business planning but directly useful for deciding which SEO keywords and audiences are actually worth chasing.
What Each Term Means
| Term | What it measures | Example |
|---|---|---|
| TAM | Total demand for the category, globally | Everyone worldwide who could ever want SEO services |
| SAM | The portion you could realistically serve given language, region, capability | English-speaking businesses in markets you operate in |
| SOM | The portion you can realistically capture given current resources and competition | What you can actually win this year given your team size |
Why It Matters for SEO
Targeting keywords sized for your TAM rather than your SOM leads to chasing enormous, hyper-competitive search terms that a smaller site has little realistic chance of ranking for. Sizing keyword targets against your actual SOM – the market you can realistically capture given current authority and resources – produces a far more achievable content and link-building plan.
How to Calculate Them
TAM comes from total market research – industry reports, total search volume across every related term globally. SAM narrows that to your actual serviceable segment – language, geography, business model fit. SOM narrows further based on realistic capture rate given current competitive position, typically a single-digit percentage of SAM for a growing business.
Frequently asked questions
Is TAM SAM SOM only useful for startups?
No. It applies to any growth planning exercise, including deciding which keyword segments and geographic markets an SEO strategy should prioritise.
How precise does the calculation need to be?
Directionally accurate is enough for most planning purposes – the goal is prioritisation, not a precise forecast down to the decimal.
Does TAM SAM SOM change over time?
Yes, and it should be revisited periodically as your capabilities, market position, and competitive landscape evolve.
Serpwize sizes keyword opportunity against realistic capture rate, not just raw search volume. See our SEO outsourcing service.
