Size the cybersecurity market you can actually serve.

TAM, SAM, and SOM answer different questions.

A bottom-up cybersecurity market model starts with potential customer organizations and the annual revenue associated with each. It is useful when planning segments, sales coverage, and a product's reachable opportunity.

• Total addressable market (TAM): annual revenue if all accounts in your defined broad market bought at the assumed annual contract value.
• Serviceable available market (SAM): the portion of that market the current product and commercial model can serve.
• Serviceable obtainable market (SOM): the portion you could realistically win within a stated time horizon and constraints.

Different teams use SOM to mean either a cumulative share of the market or new revenue won in a period. State your definition. The One Cyber calculator models annualized revenue from new wins during a 12-month acquisition window; it is not a total-company revenue forecast.

1. Count companies, not people.

Your account universe should represent potential contracts. Deduplicate subsidiaries, parent organizations, and buying entities according to how you sell. Three contacts at one company do not create three accounts. A buyer database count cannot be substituted directly for an account count.

Write down the region, industry, scale, and product requirements used to select accounts. Record the data source and observation date. Where a requirement cannot be verified, keep that account in an uncertain group rather than silently treating it as a confirmed fit.

2. Use a defensible annual contract value.

Use realized annual contract value from comparable customers when available. For a new product, define a price assumption and show low, base, and high cases. Separate recurring product revenue from one-time services. If pricing varies materially by customer size, model those segments separately and add the results.

TAM = broad eligible account count × assumed annual contract value. This is a scenario, not proof that every account needs the product, has a budget, or will buy.

3. Apply the constraints that define SAM.

Filter for the accounts your current product, sales coverage, and support model can serve. Consider supported deployment environments, geography, product requirements, and minimum or maximum customer size. Document any assumption used in place of directly counted accounts.

SAM = serviceable account count × assumed annual contract value. The calculator accepts a serviceable share of the broad account universe as a planning shortcut. Replace that percentage with a measured ratio when you have an audited account list.

4. Constrain SOM by reach and sales capacity.

Estimate how many unique serviceable accounts can enter a qualified opportunity during the next 12 months. Then estimate how many qualified opportunities the team can work. Use the lower number as the opportunity ceiling and apply an assumed opportunity-to-win rate.

Do not multiply a contact count by an opportunity win rate. The rate's denominator must match the stage it describes. Count each account once in this simplified model, and adjust separately if you sell several distinct contracts per organization.

A worked example with fictional assumptions

These numbers illustrate the arithmetic only. They are not industry benchmarks, One Cyber performance data, or a forecast. Annualized contract value is also different from revenue recognized or cash collected during the acquisition year.

Review the assumptions before using the result.

• Can you reproduce the account count and deduplication rules?
• Does each segment need a different contract-value assumption?
• Are the qualification and win-rate definitions consistent?
• Does capacity account for ramp time, existing pipeline, and sales-cycle length?
• Which assumption changes the outcome most in a conservative case?

Run your scenarios in the free TAM, SAM, and SOM calculator. Then use the ABM guide to translate the selected market into a bounded account pilot.