The market size estimator calculates TAM, SAM, and SOM — the three key market sizing metrics for business plans and investor pitches. Use both top-down and bottom-up methods to triangulate your market opportunity.
Bottom-Up Method (Most Credible)
Geographic / product fit restriction
Your 3-5 year target share
How to Estimate Market Size (TAM SAM SOM)
Market sizing is a critical skill for pitching investors and setting realistic growth targets. The TAM SAM SOM framework breaks market opportunity into three progressively smaller, more achievable segments.
TAM: Total Addressable Market
TAM represents the entire revenue opportunity if you captured 100% of the market. For a US project management SaaS: (40M knowledge workers) × ($120/year average spend) = $4.8B TAM. This is theoretical — you'll never capture 100% — but it sets the ceiling.
SAM: Serviceable Available Market
SAM filters TAM to what you can actually serve with your current product and go-to-market. If your PM software targets small businesses (under 50 employees) in North America, SAM might be 20-30% of TAM. Be specific about your filters: geography, company size, industry vertical, job function.
SOM: Serviceable Obtainable Market
SOM is the portion of SAM you can realistically win in 3-5 years. Capture rates typically range 1-10% for new entrants. If you project 5% of your SAM in Year 3, show the revenue, headcount, and sales capacity that justifies that number. SOM is what investors test hardest.
FAQ
What is TAM SAM SOM?
TAM (Total Addressable Market) is the total market demand for a product if 100% captured. SAM (Serviceable Available Market) is the portion you can realistically serve given your geography and product. SOM (Serviceable Obtainable Market) is your realistic market share in the near term.
How do I calculate TAM?
Top-down: Start with industry reports (e.g., '$50B global CRM market') and segment by relevant filters. Bottom-up: (Number of potential customers) × (Average revenue per customer). Bottom-up is more credible to investors because it's built from data you can verify.
What TAM is needed to attract VC funding?
Most VCs want TAM of $1B+. SAM should be $100M+. Your SOM (realistic 3-5 year target) should be $10-50M+. Small markets cap your growth ceiling regardless of execution quality.
Is this calculator free?
Yes, completely free with no signup required. All calculations run in your browser.