What is TAM / SAM / SOM?
A market-sizing hierarchy: Total Addressable Market (full demand), Serviceable Available Market (reachable segment), and Serviceable Obtainable Market (realistic near-term capture).
TAM, SAM, and SOM are three concentric circles of market sizing that help product and strategy teams understand the scope of a market opportunity. TAM (Total Addressable Market) is the maximum global revenue opportunity if you captured 100% of demand. SAM (Serviceable Available Market) is the portion you could realistically serve given your business model and geography. SOM (Serviceable Obtainable Market) is the realistic near-term capture given competitive dynamics and go-to-market constraints.
Formula
TAM > SAM > SOM (each subset of the previous)Top-down approach: Start with industry research reports and narrow down by geography, segment, and ICP. Example: Global CRM market TAM = $100B. SMB segment SAM = $20B. First 3-year realistic SOM = $50M. Bottom-up approach: Count addressable customers x average contract value for more credible investor presentations. SOM should represent 1-5% of SAM for early-stage businesses.
Industry Benchmarks
- Investors typically look for TAM of $1B+ for venture-scale businesses
- A credible SAM is at least $100M to support a $20M+ ARR business
- SOM for Year 1 should be achievable with current team and resources
- SOM/SAM ratio of 1-5% is typical for early-stage market entry
- Bottom-up SOM calculations are more credible than top-down in investor conversations
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 if you will capture all of it, which signals naivety to investors who expect a realistic SOM
- Using top-down TAM from research reports without validating bottom-up with actual customer counts and prices
- Failing to define the time horizon for SOM, which makes it impossible to evaluate against actual performance
- Always present both top-down and bottom-up calculations - when they converge, your market sizing is credible
- Define your Ideal Customer Profile precisely before calculating SAM - an overly broad ICP inflates SAM unrealistically
- Revisit SOM quarterly and compare against actual market share captured to calibrate future assumptions
Related Terms
Free TAM / SAM / SOM Calculator
Skip the spreadsheet. Enter your numbers in the free Market Sizing Calculator and get a benchmarked TAM / SAM / SOM result in seconds.