TAM SAM SOM Calculator

Size your market with AI.

Describe your idea and our AI estimates your TAM, SAM, and SOM — with the assumptions it used, so you can defend the numbers.

TAM

Total Addressable Market

The total global demand for your product if every potential customer bought it. A ceiling, not a target.

SAM

Serviceable Available Market

The portion of TAM you can realistically reach given your business model, geography, and channels.

SOM

Serviceable Obtainable Market

The slice of SAM you can win in the next 3–5 years given your resources and competitive position. Your actual target.

What is TAM SAM SOM?

TAM, SAM, and SOM are three concentric circles that describe market opportunity at different levels of realism. Investors use them to assess whether an opportunity is worth funding. Founders use them to set realistic targets and plan go-to-market.

TAM — Total Addressable Market

The total global revenue opportunity if you had 100% market share. It answers: "How big is this market in the best-case world?" Use this to show investors the ceiling of the opportunity. TAM is usually measured in billions.

SAM — Serviceable Available Market

The subset of TAM you can actually reach given your product, geography, distribution channels, and business model. If you're building a tool for US physiotherapists, the SAM is not the global healthcare market — it's US allied health practitioners who could benefit from your specific solution.

SOM — Serviceable Obtainable Market

The realistic share of SAM you can capture in 3–5 years, given your resources, team, and competitive position. This is your actual business target. SOM is typically 1–5% of SAM for early-stage companies. A convincing SOM comes from bottom-up math: customers × price.

How to calculate market size

There are two approaches. Use both and triangulate:

Top-Down

Start with a total industry figure from a report (e.g. “global project management software market: $7B”) and apply percentages to narrow to your slice.

$7B × 15% (SMBs) × 5% (your niche) = $52.5M SAM

Quick but often misleading. Good for illustrating the ceiling.

Bottom-Up (preferred)

Count the actual customers and multiply by your price. More work, far more credible.

500K physios × 20% reachable × $1,200/yr = $120M SAM

Investors trust this — it shows you understand your customer.

Frequently asked questions

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Why market sizing matters for your startup

Market sizing is one of the first things investors check — not because they expect your numbers to be perfect, but because how you build the estimate reveals how well you understand your customer and your market. A founder who can defend their TAM, SAM, and SOM with bottom-up math is a founder who has done the work.

It forces you to define your actual customer

You can't calculate a realistic SAM without knowing exactly who you're selling to and where they are. This exercise alone surfaces assumptions many founders never examine until it's too late.

It gives investors confidence you're not delusional

"Our TAM is $500 billion" signals that a founder has not thought carefully about their market. A tight, bottoms-up SAM with believable assumptions is far more compelling than a giant top-down number.

It helps you set go-to-market priorities

If your SOM requires capturing 15% of a market in three years, that's a serious distribution challenge that needs to be in your plan. The numbers force the strategy conversation.

4 market sizing mistakes that kill pitch credibility

These are the patterns that make investors discount your market analysis instantly.

Using total industry size as your TAM

The global healthcare market is not your TAM if you're building a scheduling tool for physiotherapists. TAM should be the total revenue opportunity for your specific type of solution — not the industry you're adjacent to.

"We just need 1% of the market"

1% of a $10B market sounds conservative but implies significant distribution reach. Investors see through this immediately. Be specific about how you reach your first 100, 1,000, and 10,000 customers instead.

No assumptions shown

A number without a methodology is a guess. The most credible market analyses show every assumption: how many potential customers exist, what percentage are reachable, what they would pay, and why. This tool shows its assumptions for this reason.

Confusing SAM with SOM

SAM is the market you could theoretically serve. SOM is what you can realistically capture given your resources, team, and stage. Early-stage companies should target 1–5% of SAM as their SOM — and should be able to explain why that percentage is achievable.