Free TAM SAM SOM Calculator
Size your market opportunity in seconds using top-down or bottom-up approaches. Calculate your Total Addressable Market, Serviceable Addressable Market, and Serviceable Obtainable Market with visual breakdowns, proportional analysis, and actionable go-to-market insights.
Two Approaches
Top-down from industry data or bottom-up from your customer metrics
Visual Breakdown
Nested circles and proportional bars show your TAM, SAM, and SOM at a glance
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How it works
Calculation Method
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Understanding TAM, SAM, and SOM
The essential framework for sizing any market opportunity
What is TAM, SAM, and SOM?
TAM, SAM, and SOM is a three-tier framework used by founders, investors, and GTM leaders to quantify market opportunity. TAM (Total Addressable Market) represents the total revenue available if you captured every potential customer. SAM (Serviceable Addressable Market) narrows this to the segment you can realistically serve with your current product, geography, and business model. SOM (Serviceable Obtainable Market) is the share of SAM you can realistically win in the near term, given your competitive position, resources, and go-to-market execution. This framework is fundamental to fundraising, strategic planning, and resource allocation.
TAM SAM SOM formulas
Top-Down TAM = Total Industry Market Size (from analyst reports)
Bottom-Up TAM = Number of Target Companies x Average Deal Value x Purchase Frequency
SAM = TAM x Addressable Percentage (filtered by geography, segment, product fit)
SOM = SAM x Obtainable Percentage (filtered by competition, resources, GTM capacity)
Top-down vs bottom-up
- -Top-down starts with a macro market figure and applies percentage filters. Quick and useful for early-stage sanity checks, but can overestimate if assumptions are loose.
- -Bottom-up builds from specific customer counts and deal sizes. More credible with investors because each assumption can be tested and validated.
- -Best practice is to use both and compare results. If they converge, your sizing is likely sound. If they diverge, investigate the assumptions.
- -For investor decks, lead with bottom-up and use top-down as a supporting reference point.
Typical SOM by company stage
Frequently Asked Questions
Everything you need to know about TAM, SAM, SOM, and market sizing
What is TAM, SAM, and SOM?
TAM (Total Addressable Market) is the total revenue opportunity if you achieved 100% market share. SAM (Serviceable Addressable Market) is the portion your product can realistically serve based on geography, segment, and capabilities. SOM (Serviceable Obtainable Market) is the share you can realistically capture in the near term. Together they form the standard framework for any market sizing exercise, from startup pitch decks to enterprise strategic planning. Understanding these metrics is critical for building a credible go-to-market strategy.
What is the difference between top-down and bottom-up market sizing?
Top-down starts with a total industry figure from analyst reports (e.g., Gartner says the CRM market is $80B) and narrows it with percentage filters for your addressable and obtainable share. Bottom-up builds from specific inputs: your target customer count, average deal value, and purchase frequency. Bottom-up is generally more credible because each assumption can be independently validated. Best practice is to run both and check that results are in the same order of magnitude.
How do I calculate TAM?
For top-down TAM, use industry reports from Gartner, Forrester, Statista, or similar analysts. For bottom-up TAM, identify every potential customer that could use your product (regardless of whether you can reach them today) and multiply by the average annual revenue per customer. For example, if 50,000 companies match your broad criteria and your average annual contract is $25,000, your TAM is $1.25 billion. Always document your assumptions so others can evaluate them.
What is a realistic SOM for a startup?
Most B2B startups realistically capture 1-5% of their SAM in the first 2-3 years. The key is to focus on a well-defined beachhead market where you can achieve meaningful penetration, then expand. Investors are sceptical of SOM projections above 10% for early-stage companies. A credible SOM with a clear plan to expand is far more compelling than an inflated number. Building an efficient outbound sales system is one of the fastest ways to start capturing your obtainable market.
Why do investors care about TAM SAM SOM?
Investors use TAM to assess whether the opportunity is large enough to generate venture-scale returns. SAM tells them whether the founder understands their realistic market scope. SOM reveals whether the team has a credible, near-term plan to capture customers. A common red flag is when founders claim a $100B TAM without explaining how they will capture even $10M of it. The best pitch decks present all three tiers with transparent assumptions and a believable expansion path from SOM to SAM over time.
How do I determine my addressable percentage for SAM?
Filter your TAM by every constraint that limits which customers you can actually serve. Common filters include geography (which countries or regions you operate in), company size (SMB, mid-market, enterprise), industry vertical, technology stack requirements, regulatory constraints, and language. For most B2B companies, SAM is 10-40% of TAM. Be conservative -- a realistic SAM builds investor credibility far more than an optimistic one.
What is the best approach for B2B SaaS market sizing?
For B2B SaaS, start with bottom-up. Use LinkedIn Sales Navigator, Crunchbase, or industry databases to count companies matching your ICP. Multiply by your average annual contract value. Then apply SAM filters (geography, company size, vertical) and SOM filters (competitive position, sales capacity, brand awareness). Complement with a top-down cross-check using analyst reports. Present both in your GTM strategy or pitch deck for maximum credibility.
How often should I update my TAM SAM SOM analysis?
Revisit your market sizing at least annually or when major changes occur: entering new geographies, launching new products, pivoting your ICP, significant competitive shifts, or pricing changes. Your SOM should be re-evaluated quarterly as your GTM execution data improves. As you close more deals and gather real customer data, your bottom-up assumptions become more precise, making your entire market sizing more credible and useful for resource allocation decisions.
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