TAM SAM SOM Calculator
Calculate Total Addressable Market, Serviceable Market, and Obtainable Market from bottom-up data.
Formula
TAM = Customers x ARPC | SAM = TAM x Serviceable% | SOM = SAM x Obtainable%
TAM is calculated by multiplying total potential customers by average revenue per customer. SAM narrows TAM to the segment your product can actually serve. SOM further narrows to the realistic near-term capture based on go-to-market capacity and competitive dynamics.
Worked Examples
Example 1: B2B SaaS Market Sizing
Problem: A project management SaaS targets 50 million potential businesses globally, charging $100/month. They can serve English-speaking markets (15% of TAM) and expect to capture 5% of SAM in year one.
Solution: TAM = 50,000,000 x $100 x 12 = $60 billion\nSAM = $60B x 15% = $9 billion\nSOM = $9B x 5% = $450 million\nSAM customers: 7.5 million businesses\nSOM customers: 375,000 businesses
Result: TAM: $60B | SAM: $9B | SOM: $450M | Market penetration: 0.75%
Example 2: Consumer App Market with Growth Projection
Problem: A fitness app targets 200 million potential users at $60/year. Serviceable market is 20% (US + EU only). Obtainable is 3% of SAM. Market grows 12% annually.
Solution: TAM = 200M x $60 = $12 billion\nSAM = $12B x 20% = $2.4 billion\nSOM = $2.4B x 3% = $72 million\nYear 5 TAM: $12B x 1.12^5 = $21.15B\nYear 5 SOM: $72M x 1.12^5 = $126.9M
Result: TAM: $12B | SAM: $2.4B | SOM: $72M | Year 5 SOM: $126.9M (12% CAGR)
Frequently Asked Questions
What are TAM, SAM, and SOM and why do investors care about them?
TAM (Total Addressable Market) is the total revenue opportunity if you captured 100% of the market. SAM (Serviceable Addressable Market) is the segment of TAM you can realistically serve with your product and business model. SOM (Serviceable Obtainable Market) is the portion of SAM you can realistically capture in the near term. Investors care about these metrics because they reveal whether a startup is targeting a market large enough to produce venture-scale returns. A TAM under $1 billion is generally considered too small for venture capital. The relationship between TAM, SAM, and SOM also demonstrates whether founders understand their competitive position and have realistic growth expectations.
How do you calculate TAM using the bottom-up approach?
The bottom-up approach calculates TAM by multiplying the number of potential customers by the average revenue per customer. Start by identifying every potential buyer of your product category globally, regardless of whether you can reach them today. Then multiply by your average annual contract value or transaction size. For example, if there are 30 million small businesses in the US and your SaaS product costs $1,200 per year, your US TAM is $36 billion. The bottom-up method is preferred by investors because it forces founders to justify each assumption with data. Compare your bottom-up estimate against top-down industry reports to validate the figure.
What is a realistic SAM percentage relative to TAM?
SAM typically ranges from 10% to 40% of TAM, depending on how narrowly your product serves the total market. The SAM is constrained by factors like geographic reach, product capabilities, pricing tier, regulatory limitations, and channel access. A B2B SaaS company serving only mid-market companies in North America might have a SAM of 15-20% of their global TAM. A consumer app available only on iOS in English-speaking countries might have 25-30% of the global TAM. The key is being honest about which segments your product actually serves well today. Investors are skeptical of SAM estimates above 50% of TAM because it suggests the founder has not thought critically about market segmentation.
How do you estimate SOM for a startup pitch deck?
SOM should be estimated based on concrete go-to-market plans and competitive analysis, typically representing 1-10% of SAM for early-stage startups. Calculate SOM by analyzing your current growth rate, sales capacity, marketing budget, and competitive win rate. A credible SOM estimate might be derived from: number of sales reps multiplied by average deals per rep multiplied by average deal size. Alternatively, model SOM based on achievable market share growth: if the market has 5 major competitors and you can win 5% of new customers, that defines your SOM. Investors prefer conservative SOM estimates backed by current traction data, rather than optimistic projections. A startup doing $1M ARR in a $500M SAM has a SOM penetration of 0.2%, leaving substantial room for growth.
How does market growth rate affect TAM SAM SOM projections?
Market growth rate determines how TAM, SAM, and SOM expand over time, which directly impacts your long-term revenue potential and investor returns. A 10% annual market growth rate means your TAM roughly doubles every 7 years, even if your market share stays constant. Fast-growing markets (20%+ annually) are attractive because new revenue is being created, making it easier to capture customers without taking them from competitors. However, high growth rates also attract more competitors and funding. When projecting market growth, use industry analyst estimates and apply them consistently across TAM, SAM, and SOM. Most pitch decks project 3-5 years forward, showing how SOM grows both from market expansion and increasing market share capture.
How should TAM SAM SOM be presented in a pitch deck?
Present TAM, SAM, and SOM as a set of three concentric circles on a single slide, with TAM as the largest outer circle, SAM as the middle ring, and SOM as the center. Include specific dollar figures and clear labels for each tier. Show your bottom-up calculation methodology in a simple formula below the circles. Add a growth projection showing how these markets expand over 3-5 years. Include a brief note on data sources to establish credibility, citing specific industry reports, government data, or your own customer research. Avoid cluttering the slide with too many numbers or caveats. The best market sizing slides tell a clear story in under 30 seconds, making investors immediately understand the opportunity size and your realistic capture plan.