Market Size Calculator
Calculate TAM, SAM and SOM for a startup or product with the top-down method (total market value narrowed down) or the bottom-up method (customers × annual revenue per customer), and project all three forward with a market growth rate.
Input
Bottom-up builds the market from customer counts and pricing. Top-down starts from a published industry figure.
Everyone who could conceivably buy this kind of product, worldwide.
Average annual revenue per customer — e.g. a $50/month plan is 600.
Share of the total market your product can actually serve — right geography, language, segment and price point.
Share of the serviceable market you can realistically win in the next few years.
Optional. Annual market growth (CAGR) — adds a projection of TAM, SAM and SOM.
How far ahead to project when a growth rate is set.
Output
| Metric | Value |
|---|---|
| No data yet | |
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/market-size-calculator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"method": "bottom-up",
"totalCustomers": "2000000",
"annualValue": "600",
"samPercent": "25",
"somPercent": "5"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `market-size-calculator` tool (Market Size Calculator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/market-size-calculator/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Market Size Calculator — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
A market size calculator turns a handful of assumptions into the three numbers every pitch deck and business plan is expected to show: TAM, SAM and SOM. This one does the arithmetic openly — every figure in the result traces back to a number you typed, so you can defend it when someone asks where it came from.
How to use it
- Pick a method.
- Bottom-up multiplies the number of potential customers by what each one pays you per year. Investors generally trust this more, because it is built from your own pricing.
- Top-down starts from a published figure for the whole industry and narrows it.
- Enter the serviceable share — the slice of the total market your product can actually serve given its geography, language, segment and price.
- Enter the obtainable share of SAM — the part of that serviceable market you can realistically capture in the next few years, given competition and your sales capacity.
- Optionally add a market growth rate to see what all three numbers look like a few years out.
The table updates as you type. Copy it or download it as CSV for a slide or spreadsheet.
The formulas
- TAM (bottom-up) = Potential Customers × Annual Revenue per Customer
- TAM (top-down) = Total Market Value
- SAM = TAM × Serviceable Share
- SOM = SAM × Obtainable Share
- Projection = Value × (1 + Growth Rate)Years
What is the difference between TAM, SAM and SOM?
TAM (Total Addressable Market) is the revenue available if you sold to every possible customer with no competition. SAM (Serviceable Addressable Market) is the part of it your product and business model can reach. SOM (Serviceable Obtainable Market) is the part of SAM you can plausibly win — it is the number that should line up with your revenue forecast.
What is a realistic obtainable share?
For a new entrant in a market with established competitors, 1–5% of SAM within three to five years is a common planning range. A claim above 10% usually needs a specific reason: a captive channel, a regulatory advantage, or a market with no real incumbent.
Should I use top-down or bottom-up?
Use both if you can. Bottom-up is more credible because it rests on customer counts and pricing you can verify. Top-down is a fast sanity check — if the two disagree by an order of magnitude, one of your assumptions is wrong.
What do I do with SOM once I have it?
Check it against your unit economics. SOM tells you how much revenue is within reach; the Customer Lifetime Value Calculator tells you whether each of those customers is worth what it costs to win, and the Break-Even Point Calculator tells you how much of that SOM you need to cover your costs.
Privacy
The calculation runs entirely in your browser. Your market figures and assumptions are never uploaded or stored, and there is no sign-up.