What is TAM SAM SOM?

TAM-SAM-SOM is the standard framework for market sizing in consulting interviews and startup pitches. TAM represents the theoretical ceiling—if you captured 100% of the market with no competition. SAM narrows this to segments you can actually serve with your current product and business model. SOM is your realistic near-term target based on competitive dynamics and go-to-market capabilities.

Two approaches exist for calculating TAM: top-down (starting with industry reports and narrowing) and bottom-up (starting with unit economics and scaling). Bottom-up is generally more credible because it forces you to articulate specific assumptions about customer counts, pricing, and adoption rates. In interviews, showing both approaches and triangulating builds confidence in your estimate.

Investors care most about SOM because it drives near-term revenue projections, but they also want large TAM/SAM to ensure the company has room to grow. A startup with a $100B TAM but $5M SOM needs a clear path to expand from SOM toward SAM. In case interviews, clearly distinguishing between these three levels shows analytical precision.