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Intermediate

What is SOM

Full name: Serviceable Obtainable Market

Definition

SOM (serviceable obtainable market) is the part of the market you can actually win with today's team, budget and hours. In a small business, capacity sets it.

Why it matters

SOM is where a market estimate meets the owner's calendar.

Common mistakes

Planning sales above what the business can physically deliver, because capacity was never counted.

Related terms

Worked exampleIllustration

The SOM of one café: the market against the counter

Illustrative numbers: one fictional café in one city, no real business.

  1. SAM

    8,000 adults live or work within a ten minute walk, each spending ₪1,500 a year on coffee out.

    ₪12,000,000

  2. Market share

    With good marketing the café could win 15% of them in its first year, 1,200 regulars.

    1,200 × ₪1,500 = ₪1,800,000

  3. Capacity

    The counter serves at most 200 orders a day, at an average of ₪25 excluding VAT, over 300 opening days.

    200 × ₪25 × 300 = ₪1,500,000

  4. SOM

    The lower number wins, so this SOM is set by capacity, about 1,000 regulars.

    ₪1,500,000

  5. The trap

    A plan that assumed 400 orders a day would have written revenue the café cannot serve.

    ₪3,000,000

SOM is the smaller of what the market would buy and what your day can deliver.

Illustration

The counter sets the limit

The market: adults in the café's city who buy coffee out, each spending ₪1,500 a year.

TAM ₪90,000,000, SAM ₪12,000,000, SOM ₪1,500,000TAMSAMSOM
  • TAMThe whole city's yearly spend₪90,000,000
  • SAMAdults within a ten minute walk₪12,000,000
  • SOMWhat the café can actually win₪1,500,000

The market would buy ₪1,800,000 (15% of 8,000 nearby adults), but 200 orders a day at ₪25 over 300 opening days serve only ₪1,500,000. The lower number is the SOM: ₪1,500,000.

Each ring's area is its yearly value in shekels, for one fictional café in one city.

The plan against the counter

400 orders a day on paper, 200 over the counter. The difference is revenue the café cannot serve.

Definition

SOM is the part of the serviceable addressable market (SAM) that a business can realistically win over the next few years, given its competitors, its marketing budget and what it can deliver. There are two ways to estimate it. Top down takes the share of SAM the business could win. Bottom up counts what its capacity can serve: seats, hours, staff or stock. For a small business the lower of the two is the SOM, and it is usually capacity that binds. SOM is still a market size estimate, but it is the one closest to a sales plan.

Why it matters

A plan built on SAM or on a hopeful market share writes revenue that the team, the counter or the diary cannot deliver, and the business hires, buys and borrows for it. For a one location business the calendar is often the market: its hours and seats decide more than the number of customers nearby.

Directly related: TAM, SAM, Bottleneck.

Formula

SOM = Customers You Can Reach * Share You Can Win * Average Yearly Spend per Customer

Improvement tips

  • Estimate SOM twice, as a share of SAM and from your capacity, and keep the lower number.
  • Write capacity in the unit the business sells: orders a day, treatments a week, rooms a night.
  • Set the market share from evidence, such as early sign ups or a competitor you can observe, not from a round 1%.
  • Calculate SOM again when capacity changes, because a second counter, a new hire or a longer day moves it.

Common mistakes

  • Assuming a market share such as 1% of SAM with no evidence or marketing plan behind it.
  • Calling SOM the first month's sales target, when it describes what the business can win over the next few years.
TAM vs SAM vs SOM

Related terms

StartupsIntermediate

TAM

TAM (total addressable market) is the revenue you would earn if every customer in the market you defined bought from you. It is a ceiling, not a sales forecast.

StartupsIntermediate

SAM

SAM (serviceable addressable market) is the part of TAM your business can actually reach, given its location, hours, language, licences and business model.

OperationsBeginner

Bottleneck

A bottleneck is the slowest step in a process, the one that sets how much the whole business can deliver. In a small business, it is often the owner.

OperationsBeginner

Capacity

Capacity is the most work a business can deliver in a set period with its current people, tools and hours. Booking it to 100% creates queues and delays.

FinanceBeginner

Revenue

Revenue is everything a business sold in a period, before any costs and without the VAT on the invoice. It is the P&L's top line, not profit and not cash.

Quick check

A café's market share estimate gives ₪1,800,000 a year, and its counter can serve ₪1,500,000 a year. What is its SOM?

Choose an answer

Frequently asked questions

What is SOM in simple words?
The part of your market you can realistically win and serve with the team, budget and hours you have. It is the smallest of the three market circles, inside SAM and TAM.
What does SOM stand for?
Serviceable obtainable market: the part of the serviceable addressable market a business can actually obtain.
How do I calculate SOM bottom up?
Multiply the customers you can reach by the share of them you can win and by what each spends a year. Then compare the result with what your capacity can deliver, and keep the lower number.
What time horizon does SOM cover?
The next few years, not just the first month. A first year figure is one point on that path, and it grows as marketing and capacity grow.
Why does capacity matter so much for a small business?
Because it binds first. A café with one counter, a clinic with two rooms or a technician with one van cannot serve more than their day allows, however many customers live nearby.
Can I estimate SOM without sales history?
Yes. Count your capacity, which you know, and estimate a share of SAM from early evidence such as sign ups, pre orders or a competitor you can observe.
How does SOM protect a business from early mistakes?
It keeps fixed costs in line with what the business can actually sell. Rent, staff and stock planned for a bigger number drain cash.
How is SOM different from SAM?
SAM is everyone the business could reach. SOM is the part it can actually win and serve, after competition and capacity.
How can a business grow its SOM without hiring?
By getting more out of what it has: a faster process, better scheduling, online orders, or longer hours on the busiest days.
What goes wrong when a plan ignores SOM?
The plan counts customers the business cannot serve. Revenue falls short while costs were set for the bigger number.
Is SOM the same as market share?
No. Market share is the percentage of a market's sales a business already has. SOM is an estimate, in money, of what it can win, and in a small business it is often set by capacity rather than by share.
Do I need a consultant to calculate my SOM?
Not for a first estimate, since you know your capacity better than anyone. An outside view helps when the share you expect to win rests on hope rather than evidence.

Sources: Steve Blank and Bob Dorf, The Startup Owner's Manual (2012)

Last reviewed: 2026-09-24

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