TAM SAM SOM Calculator

What is this?

TAM (Total Addressable Market) is the total revenue opportunity if you captured 100% of your market. SAM (Serviceable Addressable Market) is the portion of TAM you can realistically target given your product, geography, and business model. SOM (Serviceable Obtainable Market) is the share of SAM you can capture in the near term. These three layers help investors and founders assess the size and realism of a market opportunity.

Why it matters

Every investor pitch requires market sizing. TAM shows the ceiling of opportunity, but SOM shows what is actually achievable and demonstrates that you think realistically about growth. Overstating your TAM without a credible SAM/SOM breakdown is one of the fastest ways to lose investor credibility. A bottoms-up SOM calculation is especially convincing because it is grounded in real unit economics.

How to use this calculator

Use the top-down method to start with the total industry market size (from Gartner, Statista, or industry reports), then narrow it by your serviceable percentage (your target segment) and your obtainable percentage (realistic market share in 3-5 years). Switch to bottom-up to calculate from unit economics: multiply your average revenue per customer by the number of potential customers you can reach. The best pitches include both approaches.