Estimate your TAM SAM SOM market size with sources
Investors ask "how big is this market?" and a single number pulled from a press release will not survive the next question. This prompt has your agent research the market, build a bottom-up TAM, SAM and SOM in Excel with every assumption visible, cross-check it top-down, and hand you one clean slide for your deck.
The prompt
- Estimate the TAM, SAM and SOM for [YOUR PRODUCT] sold to [TARGET CUSTOMER] in [REGIONS]. Our price is [PRICE PER CUSTOMER PER YEAR]. Research how many potential customers exist, using public statistics and industry reports, and list every source with a link. Build it bottom-up (number of customers x annual price) and check it top-down against published market estimates. For SAM, narrow to the segment we can actually serve today: [WHAT LIMITS OUR REACH]. For SOM, assume a realistic share we can win in 3 to 5 years and explain why. Deliver an Excel file with one tab per layer, all assumptions in yellow cells I can change, and a one-slide PowerPoint summary with three nested circles.
What to change
- [YOUR PRODUCT]: What you sell, e.g. "scheduling software for physiotherapy clinics".
- [TARGET CUSTOMER]: Who pays, e.g. "independent clinics with 1 to 10 therapists".
- [REGIONS]: Where you sell, e.g. "Germany, Austria and Switzerland" or "the US".
- [PRICE PER CUSTOMER PER YEAR]: Average yearly revenue per customer, e.g. "$1,200" (or monthly price x 12).
- [WHAT LIMITS OUR REACH]: Language, integrations, sales channel or size limits, e.g. "German-language only, clinics using our booking partner".
Example result
- Example: scheduling software for physiotherapy clinics (DACH)
- All figures below are illustrative assumptions for the example, not real market data.
- TAM (total addressable market)
- • Physiotherapy practices in Germany, Austria and Switzerland: about 48,000 (from national health statistics, linked in the file)
- • Average price: $1,200 per clinic per year
- • TAM = 48,000 x $1,200 = $57.6M per year
- SAM (serviceable available market)
- • Keep only independent clinics with 1 to 10 therapists: about 70% of practices, so 33,600
- • Keep only clinics that can use our booking partner integration: about 60%, so 20,160
- • SAM = 20,160 x $1,200 = $24.2M per year
- SOM (serviceable obtainable market)
- • Realistic share in 5 years with 2 sales reps and partner referrals: 4%
- • SOM = 806 clinics x $1,200 = about $0.97M ARR
- • Why 4%: comparable vertical SaaS tools in small regulated markets often reach low single-digit share in their first years. Adjust in cell B6.
- Top-down cross-check
- • A published industry report puts DACH practice-management software spend in a similar range to our TAM
- • The two methods land within 20% of each other, so the bottom-up number is credible
- How to present it
- • Lead with SOM, not TAM: "We can reach about $1M ARR from 800 clinics we can already serve."
- • Show the funnel from TAM to SOM on one slide with the three nested circles
- • Put sources in the appendix so investors can check them
- What is in the Excel file
- • Tab 1 TAM, Tab 2 SAM filters, Tab 3 SOM scenarios (2%, 4%, 6%)
- • Tab 4 Sources: title, publisher, year and link for each number
How to do it with todo.is
- Copy the prompt and fill in your product, customer, regions and price.
- Paste it into todo.is on the Today screen, or message your agent on WhatsApp or Telegram.
- Your agent researches customer counts, shows its sources and builds the Excel model and slide.
- Change the yellow cells to test scenarios, or ask "redo SOM with 3% share and add the UK".
Tips for a better result
- Build bottom-up first. Investors trust "number of customers x price" more than a big percentage of a huge report figure.
- Make SAM honest: filter by what you can sell today (language, integrations, channel), not by what you might build later.
- Check the date of every source. Market reports older than 3 years can be far off in fast-moving categories.
- Keep the slide simple: three circles, three numbers, one sentence on how you calculated them.
TAM SAM SOM market size: FAQ
- What is the difference between TAM, SAM and SOM? TAM is total demand for your type of product, SAM is the part your business model and reach can serve, and SOM is the share you can realistically win in the next few years.
- Should I use top-down or bottom-up market sizing? Use both. Bottom-up (customers x price) is more convincing, and a top-down figure from published reports is a useful sanity check.
- How big should SOM be compared to SAM? There is no fixed rule. Early-stage startups usually show a SOM of a few percent of SAM and explain the sales plan behind it.
- Are the numbers my agent finds always accurate? Your agent links every source so you can check it. Public statistics vary, so treat the result as a well-sourced estimate and review key figures yourself.
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