Total Addressable Market, Serviceable Available Market, and Serviceable Obtainable Market explained with formulas, examples, and what investors actually want to see.
Total Addressable Market
The entire revenue opportunity if you captured every possible customerin the defined market, before narrowing it to what your business can serve or win.
Shows the scale of the defined opportunity. Funding needs and investor expectations vary.
Serviceable Available Market
The portion of TAM you can realistically target given your business model, geography, pricing, and product capabilities.
Shows investors your go-to-market focus and that you understand your competitive position.
Serviceable Obtainable Market
The portion of SAM you can realistically capture in the near term given competition, sales capacity, and execution constraints.
Connects a market estimate to sales capacity and an explicit planning period.
TAM, SAM, and SOM are concentric circles. SOM sits inside SAM which sits inside TAM. Use the same revenue period for all three. The figures below are hypothetical annual market sizes, not current market estimates.
Top-Down Approach
TAM = Total Market Revenue (from industry reports) x Relevant Segment %Hypothetical example: Global HR software market = $30B. Focus on performance management = 25%. TAM = $7.5B
Bottom-Up Approach
TAM = Number of Potential Customers x Average Revenue Per CustomerHypothetical example: 5 million SMBs globally x $1,500 ACV = $7.5B TAM
SAM = TAM x (Addressable Segment % based on geography, ICP, pricing fit)Example: TAM = $7.5B. You only serve US and Canada (20% of global market), companies with 10-200 employees (assumed 30% of that regional market by revenue). SAM = $7.5B x 0.20 x 0.30 = $450M
SOM = SAM x Realistic Market Share % (based on growth rate and sales capacity)Hypothetical example: SAM = $450M and current ARR = $2M. If ARR doubles each year for three years, it reaches $16M, about 3.6% of SAM. Check this assumption against sales capacity and retention. A sales model can estimate new ARR as qualified opportunities x win rate x annual deal value.
| Criteria | TAM | SAM | SOM |
|---|---|---|---|
| Full Name | Total Addressable Market | Serviceable Available Market | Serviceable Obtainable Market |
| What It Shows | Revenue opportunity in the defined market | Realistic target segment | Near-term capture potential |
| Time Horizon | Annual market opportunity at a stated date | Serviceable market at a stated date | 1-3 year operating plan |
| Calculation Method | Top-down from industry reports or bottom-up from ICP count | TAM filtered by your ICP, geography, and pricing | SAM x realistic market share or sales capacity model |
| Accounts for Competition? | No | Partially (segment focus) | Yes (win rate and share assumptions) |
| Hypothetical CRM example above | $80B annual TAM | $12B annual SAM | $240M annual revenue at assumed year-3 share |
| Key supporting evidence | Market definition and reliable source data | Target segment and ability to serve it | Sales capacity, retention, and competitive assumptions |
| Primary Risk | Too broad, includes irrelevant segments | Too narrow or too wide based on ICP assumptions | Overoptimistic market share claims |
| Best Source Data | IDC, Gartner, McKinsey, Statista reports | LinkedIn TAM filters, CRM data, pricing analysis | Pipeline data, sales velocity, win rate history |
Start with the total industry size from a credible report and apply segmentation percentages to narrow down to your target.
Build from your own unit economics: count potential customers and multiply by your average deal size to arrive at a market estimate.
Claiming 1% of a massive market
"We only need 1% of the $500B market" is a red flag for investors. It signals you have not thought carefully about your go-to-market. Sophisticated investors want to see your path to your first $10M, not a percentage of a vague total.
Using TAM and SOM interchangeably
Presenting a $50B TAM as your near-term opportunity is misleading. Always clearly label which market size you are referencing and be explicit about the assumptions behind each number.
Defining TAM too broadly to inflate the number
A project management tool for construction companies should size demand for its software, rather than count all construction spending. Overly broad TAM definitions reduce your credibility and make SAM harder to defend.
Not updating market sizing as the business evolves
Market sizing from your Series A pitch may be completely wrong by Series B. As you learn more about your ICP and win patterns, update your SAM and SOM to reflect actual market dynamics rather than sticking to original assumptions.
Use our free Market Sizing calculator to walk through a structured TAM/SAM/SOM analysis using top-down and bottom-up estimates. Review the assumptions before using the results in a plan or pitch.
TAM is the total revenue opportunity in your defined market. SAM is the portion your product and business can serve. SOM is the portion you expect to capture over a stated period, given competition and capacity. SOM sits within SAM, which sits within TAM.
Top-down sizing narrows a market estimate with supported segment shares. Bottom-up sizing multiplies relevant customer counts by annual revenue per customer. For example, 50,000 target companies at $2,000 a year gives $100M. Estimate SOM from a justified share or a sales-capacity model, with an explicit timeframe.
TAM shows opportunity size, SAM shows the segment you can serve, and SOM connects that segment to an achievable plan. A percentage of a large market is not enough on its own; explain customer demand, pricing, sales capacity, and competition.
There is no universal TAM, SAM, or SOM minimum. The opportunity has to fit the business and the investor's return expectations. State the period and evidence behind each estimate, and show how customer growth and revenue assumptions support the proposed scale.