TAM SAM SOM calculator
Bottom-up market sizing that survives a due diligence conversation. See the formula, change the inputs and save your results.
On this page 6 sections
The short answer
TAM SAM SOM uses companies that fit your profile worldwide, realistic annual contract value, share you can actually sell to today and the additional inputs below to estimate serviceable obtainable market. Change the example inputs to your own figures. The result is a planning calculation, not an industry benchmark or a prediction.
Key points before you start
Use this tool alongside the saas market guide. Bottom-up market sizing that survives a due diligence conversation.
Your numbers
Defaults are illustrative inputs, not industry benchmarks. Use one consistent reporting period.
Results
Editable CSV worksheet
Save your marketing measurement plan
Keep a worksheet for your inputs, assumptions and next actions. You can also print the calculation directly from your browser.
How to read this
- Top-down sizing from an analyst report is the fastest way to lose credibility in a fundraise. Count companies, multiply by a price you have actually charged.
Which inputs do you need?
| Input | Example value | What to check |
|---|---|---|
| Companies that fit your profile worldwide | 240,000 | Use the value from the same reporting period as the other inputs. |
| Realistic annual contract value | 14,000 | Use the value from the same reporting period as the other inputs. |
| Share you can actually sell to today | 22% | Geography, language, compliance, integrations |
| Share of that you can win in five years | 4% | Use the value from the same reporting period as the other inputs. |
Before entering numbers, choose the unit of analysis. An account, a user and a paying subscription are different objects. Counting users in one field and accounts in another can produce a precise answer to the wrong question. Record the start and end dates beside your source export so another person can reproduce your work.
What formulas does the calculator use?
Total addressable market
tam = companies * acvThis output is expressed as currency in the same units as the inputs.
Serviceable addressable market
sam = tam * serviceable / 100This output is expressed as currency in the same units as the inputs.
Serviceable obtainable market
som = sam * obtainable / 100This output is expressed as currency in the same units as the inputs.
Accounts that represents
accounts = acv > 0 ? (sam * obtainable / 100) / acv : NaNThis output is expressed as a number.
Accounts to win per year
peryear = acv > 0 ? ((sam * obtainable / 100) / acv) / 5 : NaNThis output is expressed as a number.
Percent fields use whole percentages: enter 5 for five percent. The formula divides by 100 where a decimal rate is needed. Values in the formulas correspond to the labelled inputs above; earlier outputs can be used by later formulas.
Worked example
The defaults are a constructed scenario, not results from a named company or survey. With the example inputs above, the calculation produces:
| Output | Example result |
|---|---|
| Total addressable market | 3,360,000,000 |
| Serviceable addressable market | 739,200,000 |
| Serviceable obtainable market | 29,568,000 |
| Accounts that represents | 2,112 |
| Accounts to win per year | 422.4 |
Change one assumption at a time and watch the main result. Then test a conservative case by reducing the expected benefit or increasing the associated cost. If a decision works only at the most optimistic settings, investigate the uncertain input before committing the budget.
How should you interpret the result?
- Top-down sizing from an analyst report is the fastest way to lose credibility in a fundraise. Count companies, multiply by a price you have actually charged.
A formula describes the assumptions entered into it. It cannot establish that a channel caused a sale, that historical retention will continue, or that a projected cost is achievable. Compare the output with your own previous cohorts before using a broad market comparison.
For a management review, save the result together with the source date, segment, owner and planned action. Recalculate when the underlying input changes. Keep a separate copy of the original scenario so the team can explain the difference between the plan and the observed outcome.
Continue the analysis
Use the metrics guide to align definitions, browse all calculators for adjacent calculations, and keep a measurement worksheet beside the model. The pricing hub and growth hub cover decisions that often change these inputs.
Apply tam sam som calculator in a working review
Record the source and unit of every input before using the result. Change one assumption at a time to understand which inputs matter most. Keep outputs that describe money, time and percentages distinct, and preserve undefined cases rather than converting them into plausible-looking zeroes.
For this topic, involve the research owner and the person using the estimate for a decision and work from source method, market boundary and assumption table. The relevant unit is a clearly defined population, period and value measure. State the question the review should resolve before choosing a chart, an asset or a tool. If participants disagree about the unit or scope, resolve that disagreement before combining their evidence.
Evidence to prepare
Read the original definition before combining figures. Publication date, collection period and forecast horizon answer different questions. A market estimate can be useful without being directly comparable to another publisher’s number.
| Review field | What to record |
|---|---|
| Topic | TAM SAM SOM calculator |
| Decision | The specific action this explanation should help you choose |
| Working evidence | source method, market boundary and assumption table |
| Unit and scope | a clearly defined population, period and value measure |
| Responsible people | research owner and the person using the estimate for a decision |
| Remaining uncertainty | The missing fact that could change the decision |
Two situations that can change the interpretation
When competitor count is treated as demand
A crowded category may contain many small tools serving different jobs rather than one homogeneous market.
Use this check: Separate evidence of supply from evidence of customer problems, spending and switching behavior. Few competitors can indicate opportunity or lack of demand; the count alone does not decide.
The focused diagnostic guide provides the correction process and a working evidence sheet.
When market share has no stable denominator
A vendor’s share of tracked search mentions cannot be presented as its share of customer spending.
Use this check: Define the geography, product boundary, time period and value or volume measure. Search visibility share and revenue market share are different measures.
The focused diagnostic guide provides the correction process and a working evidence sheet.
Record the decision and the limit
A software-revenue estimate and a broader customer-spending estimate may both be credible within their own definitions. Averaging them does not create a better answer. Explain the boundary and choose the measure that matches the decision being made.
Keep the conclusion beside the evidence that supports it. Record what the team will do, who owns the next action and which event or date will trigger a review. If the underlying definition, audience or product behavior changes, revisit the conclusion rather than assuming the old result still applies. A clear limit is useful information; it tells the next reader where additional investigation is required.
Use the complete topic collection for related methods and the category field guides when the product’s buying situation or implementation requirements change how the method should be applied.
A reproducible sensitivity exercise
The tam sam som calculator tool provides a related numerical exercise. Its current default inputs are constructed examples, not industry observations. Under those defaults, the output labelled Serviceable obtainable market is 29,568,000 in the tool’s displayed units. The table changes one input at a time and leaves the others at their defaults.
| Input changed | Default input | Alternative input | Serviceable obtainable market after change |
|---|---|---|---|
| Companies that fit your profile worldwide | 240,000 | 288,000 | 35,481,600 |
| Realistic annual contract value | 14,000 | 16,800 | 35,481,600 |
| Share you can actually sell to today | 22 | 26.4 | 35,481,600 |
| Share of that you can win in five years | 4 | 4.8 | 35,481,600 |
The alternative inputs are sensitivity cases, not recommended targets. A result marked not defined means the proposed combination does not satisfy the model or produces an undefined ratio. Keep that state visible. If the output changes sharply after a small input change, investigate the uncertain input before using the model to justify a larger commitment.
Compare the model’s scope with the concept on this page. The calculator may represent one particular application rather than every use of the term. Record the reporting period, currency where relevant, and the source of the real values you enter.
Editable CSV worksheet
Save your marketing measurement plan
Keep a worksheet for your inputs, assumptions and next actions. You can also print the calculation directly from your browser.
Frequently asked questions
How does this tam sam som calculator work?
It evaluates the formulas shown on this page in your browser. Bottom-up market sizing that survives a due diligence conversation. Inputs are not sent to a calculation server.
Are the default values SaaS industry benchmarks?
No. They are example inputs chosen to demonstrate the calculation. Replace them with your billing, CRM or finance records before making a decision.
Why does a result show n/a?
The calculation is undefined or an input is outside its allowed range. Check for an empty field, a zero denominator or an impossible percentage before interpreting the result.
Can I save or share my calculation?
Use Print or save results to create a local PDF with your browser. Review the inputs before sharing and remove confidential customer or company information.
The saas-marketing.net editorial team Research and editorial
We research, write and maintain every page on this site. The library explains marketing decisions through practical frameworks, explicit assumptions and references. Corrections can be requested through the contact page.
Published September 17, 2026. Last updated .