What is TAM (total addressable market)?
Total addressable market is the full revenue opportunity available if every company that could buy a product did buy it. In go-to-market work TAM is usually counted in accounts rather than currency: the number of real companies matching the ideal customer profile.
Why it matters
TAM sets the ceiling on what the current motion can produce. It is the number that says whether a target is reachable with the segment you sell to today, or whether reaching it requires a new segment, a new region, or a new product.
How TAM is sized
- Write the ICP as filters against fields a dataset actually holds.
- Count the companies matching those filters, rather than estimating down from an analyst's market figure.
- Subtract what you cannot serve — unsupported regions, existing customers, accounts already disqualified.
- Count the buying roles inside each account, since coverage is measured in contacts rather than in logos.
- Recount whenever the ICP changes, because TAM is a function of the ICP and not an independent fact.
TAM, SAM and SOM
| Term | What it counts | Question it answers |
|---|---|---|
| TAM | Every company that could buy | How large is the ceiling |
| SAM | The part of TAM you can serve today | What the current product and regions reach |
| SOM | The part of SAM you can realistically win | What this year’s plan can be built on |
Common mistakes
- Taking a top-down figure from a market report and presenting it as an account count. The two are different units.
- Counting companies the product cannot serve — wrong region, wrong size, unsupported stack.
- Counting accounts and assuming contact coverage follows. An addressable account with no reachable buyer is not addressable.
- Treating the number as fixed. Change the ICP and the market changes with it.