What is TAM / SAM / SOM?
TAM, SAM, and SOM are market-sizing concepts that help product and strategy teams describe an opportunity at different levels. TAM (Total Addressable Market) is the revenue opportunity under a broad market definition. SAM (Serviceable Available Market) is the portion a company can serve given its business model and geography. SOM (Serviceable Obtainable Market) is the portion it expects to capture within a stated time horizon, given competitive and go-to-market constraints.
Formula
TAM >= SAM >= SOM (each is a subset of the previous)A top-down approach starts with industry research and narrows it by geography, segment, and ideal customer profile. A bottom-up approach estimates the number of addressable customers and their average contract value. Compare the assumptions behind both approaches and state the time horizon used for SOM.
Benchmarks and interpretation
- Assess whether the market can support the company’s planned revenue model, growth rate, and return expectations
- Explain how the SAM definition connects to the customer segments, prices, and sales capacity in the plan
- Set a SOM target against a stated time horizon, competitive alternatives, and execution assumptions
- Use market-share assumptions that can be explained by distribution, customer adoption, and operating capacity
- Compare top-down and bottom-up estimates to test whether their assumptions are consistent
When to use TAM / SAM / SOM
- Building the market opportunity slide in a fundraising deck
- Making resource allocation decisions based on the relative size of different market segments
- Validating whether a new product category is large enough to justify investment
- Setting realistic revenue targets for a new market entry or product launch
- Presenting TAM as expected revenue rather than distinguishing it from a time-bound SOM estimate
- Using a top-down market estimate without checking it against customer counts, prices, and distribution assumptions
- Failing to define the time horizon for SOM, which makes it impossible to evaluate against actual performance
- Compare top-down and bottom-up calculations, then document where their assumptions differ
- Define the Ideal Customer Profile before calculating SAM so the included segment is clear
- Revisit SOM quarterly and compare against actual market share captured to calibrate future assumptions
Related terms
Free TAM / SAM / SOM Calculator
Enter your inputs in the free Market Sizing Calculator and review the result alongside its guidance.