For consultants sizing a client's market
TAM SAM SOM Calculator With Sourced Figures
Paste what the client sells, to whom and where, or drop the deck. Get TAM, SAM and SOM built two ways, every figure sourced.
Free to start. No card needed.
| Layer | Calculation | Size | Source |
|---|---|---|---|
| TAM | 5,121 community hospitals × $36,000 | $184.4M | AHA Fast Facts 2026 · your notes |
| SAM | 1,797 rural hospitals × $36,000 | $64.7M | AHA Fast Facts 2026 |
| SOM, year 3 | 72 hospitals × $36,000 | $2.6M | Your notes: 2 sellers × 12 a year |
| Top-down check | $1.2B × 25% for nurse scheduling | $300M | Your notes · 25% is an estimate |
Top-down lands at 1.6 times the bottom-up TAM. Price per hospital moves the answer most.
What you'll get
TAM, SAM and SOM built two ways, with every figure sourced
- Top-down and bottom-up sizing tables side by side, with the gap explained
- Every assumption with its source: a public link, your notes, or marked to check
- SAM and SOM logic, and the three assumptions that move the answer most
Before and after
Your client's brief in. A market size you can defend.
Nurse-scheduling software for US hospitals, $36,000 a year per hospital. Sold only to rural hospitals so far. Two salespeople, each closing about 12 hospitals a year. The board pack says hospital workforce software is a $1.2 billion market, with no source.
Bottom-up. TAM: 5,121 community hospitals × $36,000 = $184.4M. Count: AHA Fast Facts 2026, linked. Price: from your notes. SAM: 1,797 rural community hospitals × $36,000 = $64.7M. Count: same source. SOM by year 3: 2 sellers × 12 hospitals × 3 years = 72 hospitals, or $2.6M a year. That is 4% of SAM. Top-down. $1.2B hospital workforce software (from your notes, report not named) × 25% for nurse scheduling (estimate, to check) = $300M. Sanity check: top-down is 1.6 times the bottom-up TAM. The report may count federal hospitals and other products. Moves the answer most: price per hospital, the 25% share, then 12 hospitals per seller a year.
Each figure carries its source, so you know which ones to confirm before the client sees them.
Why it works
What is TAM, SAM and SOM, and how do you calculate it?
TAM SAM SOM is a way to size a market in three nested layers, each a yearly revenue figure. TAM is the total addressable market, SAM is the serviceable part your client can actually reach, and SOM is the share it can realistically win in the next few years. River's TAM SAM SOM calculator builds all three twice, top-down from a published total and bottom-up from a count of buyers. Every assumption lands in a table with its source, so you can check each line before it reaches a slide.
Most calculators multiply the three numbers you type in, so the answer is only as good as your guesses. River does the research step as well. It reads your notes or deck, then looks up public counts and totals, such as government business statistics or a trade body's figures, and links each one. Figures from your own material are marked "from your notes". Anything with no source is marked "(estimate, to check)", and River never fills a gap with a statistic it cannot show you.
Use it when a client asks how big an opportunity is: a new segment, a new region, a product launch or a business plan going to investors. Drop the pitch deck or plan, or paste a few lines on what the client sells, to whom and where. If the market question sits inside a bigger strategy problem, break it down first with the issue tree template, and test the client's position with the SWOT analysis generator. Then give the market slide a clear claim with the action title generator.
What lands in your doc
What's in your market sizing
- A top-down sizing that starts from a published market total and narrows it step by step
- A bottom-up sizing that counts the possible buyers and multiplies by what each pays a year
- An assumptions table: every figure linked to its source, marked from your notes, or flagged to check
- SAM and SOM worked out in plain steps, from who the client can reach and win
- A sanity check that sets the two methods side by side and explains the gap between them
- The three assumptions that move the answer most, each recalculated at a low and a high value
How it works
From a client brief to TAM, SAM and SOM
Paste or drop
Paste what the client sells, to whom and where, or drop the pitch deck or business plan.
River finds the figures
It reads everything first, then looks up public counts and totals and opens every source it cites.
Get your sizing
Top-down and bottom-up tables, SAM and SOM logic and a sanity check land in your doc.
Test the assumptions
Change a figure and ask River to rerun the numbers, or turn the sizing into a market slide.
How to calculate TAM, SAM and SOM by hand
Build the market twice. Top-down market sizing starts from a published total for the whole category and narrows it with filters for region, segment and product. Bottom-up counts the buyers who could use the offer and multiplies by what each one pays in a year. The SBA's market research guide lists federal data sources for those counts, such as the Census Business Builder. Check what each source covers: the Census Bureau's County Business Patterns counts only establishments with paid employees.
Here is a worked example: the client is invented, but the hospital counts are real. It sells nurse-scheduling software to US hospitals at $36,000 a year per hospital. The American Hospital Association's Fast Facts on U.S. Hospitals counts 5,121 community hospitals, 1,797 of them rural, from its 2024 survey. Bottom-up, TAM is 5,121 × $36,000, about $184 million. The client sells only to rural hospitals, so SAM is 1,797 × $36,000, about $65 million. Two salespeople closing 12 hospitals a year each win 72 in three years: a SOM of $2.6 million a year.
Then compare the two methods and test the assumptions. Suppose the client's board pack puts hospital workforce software at $1.2 billion, and nurse scheduling is a quarter of that: $300 million, or 1.6 times the bottom-up TAM. Don't average the two. Explain the gap instead: the report may include federal hospitals, other products or larger systems paying more. Last, change each assumption by a plausible amount and watch SOM. Here, price moves every layer and sales capacity moves only SOM, so those are the two to confirm first.
Questions consultants ask
Common questions
What is TAM, SAM and SOM?
TAM, SAM and SOM are three nested estimates of a market's yearly revenue. TAM, the total addressable market, counts every buyer who could use the offer. SAM, the serviceable available market, is the part the business can reach with its product, channels and geography. SOM, the serviceable obtainable market, is the share it can realistically win in a stated period, such as three years.
How do you calculate TAM, SAM and SOM?
Bottom-up, multiply the number of possible buyers by what one pays a year to get TAM, then keep only the buyers the client can serve to get SAM. Top-down, start from a published market total and apply filters for region, segment and product. For SOM, work from capacity: how many customers the client can win and serve each year, times the price.
What is the difference between top-down and bottom-up market sizing?
Top-down starts from a published total for the whole category, such as an industry report, and narrows it. It is quick, but it inherits whatever the report chose to include. Bottom-up counts buyers and multiplies by price, so every input can be checked. River builds both, shows how far apart they land, and explains the gap instead of averaging it away.
Where do the numbers come from?
From two places, and the doc says which. Figures in your notes, deck or plan are marked "from your notes", with the file and page. Public figures come from River's web research, such as government statistics and trade bodies, each linked to the page River opened. If no page can be opened for a figure, the doc says so and marks the figure to check.
What is a realistic SOM?
One the client can explain from its own capacity. Count how many customers its salespeople, partners or delivery team can win and serve each year, then multiply by the price. A round share of SAM, such as "we only need 1%", is a hope rather than evidence. River shows SOM as a figure and as a share of SAM, with the year-by-year working.
Can it size the market from a pitch deck or business plan?
Yes. Drop up to ten files, as PowerPoint, PDF, Word or Excel, and River reads them in full before it starts. It picks out what the client sells, to whom, where and at what price, and checks any market figures the deck already quotes. Where a figure in the deck has no source, the assumptions table says so.
Is my client's business plan private?
Files you drop stay in your own River space unless you share them. Under River's privacy policy, nothing you upload is used to train AI models, and River's AI providers are bound by their agreements with River not to train on it. If the plan is confidential, check your client agreement before you upload it.
Your next step
More for your project
Size the market with numbers you can defend
Paste what the client sells, to whom and where, or drop the deck. Every figure arrives with its source or a flag to check it.