TAM, SAM, SOM

TAM, SAM, and SOM are three nested ways to size a market, moving from the theoretical maximum down to what you can realistically capture. TAM (Total Addressable Market) is the entire revenue opportunity if every possible buyer bought. SAM (Serviceable Addressable Market) narrows that to the portion you can actually serve given your product, geography, and segment. SOM (Serviceable Obtainable Market) narrows it again to the share you can plausibly win in a defined period, given your capacity and competition.

Why it matters for outbound

Outbound only works against a market large enough to feed it but specific enough to target. These three numbers tell you whether your ICP is too broad to be credible or too narrow to hit a number. The SAM defines the universe a list-building team can actually compile, and the SOM grounds the pipeline coverage math: if your obtainable market is a few hundred accounts, your motion and forecast must reflect that, not a fantasy TAM.

How it works

The figures are built top-down and validated bottom-up.

• TAM: total companies that fit the category, times average contract value.
• SAM: filter the TAM by who your ICP and offer can genuinely serve.
• SOM: apply realistic win rates and capacity to the SAM to get a target you can defend.

Honest sizing keeps a go-to-market plan credible. We pressure-test it inside our outbound strategy and GTM service.