Serviceable addressable market (SAM): what it is and how to size it

Most market sizing slides have a middle number that nobody trusts. The total addressable market at the top is a research-report figure everyone nods at. The obtainable number at the bottom is a sales target with a bow on it. In between sits the serviceable addressable market, and it is usually the softest of the three, because it is the one people fudge to make the story work.

Your serviceable addressable market (SAM) is the part of your total market that your business, as it exists today, can actually sell to. Not the market you could reach after you build three more features and open two new regions. The market your current product, your current pricing, and the places you are legally and practically able to operate can serve right now. Get this number honest and the rest of your go-to-market planning has something real to stand on. Get it wrong and you are staffing a sales team against a fantasy.

This piece sits under our guide to TAM, SAM and SOM, and it goes deep on the middle number specifically. If you want the whole framework first, start there and come back.

What SAM actually is

SAM is the subset of your total addressable market that fits within the boundaries of what you can serve. Those boundaries are not aspirational. They are the hard edges of your current business.

A few of them come up in almost every sizing exercise we run:

• Product fit. Does what you have built solve the problem this buyer has, without a heroic amount of custom work or a roadmap promise?
• Geography. If you can only invoice in three countries, or your support team only covers two time zones, companies outside them are not in your SAM no matter how well they fit otherwise.
• Segment. A tool priced and packaged for a 40-person sales team does not serve a two-person startup or a 4,000-seat enterprise, even if both technically have the problem.
• Language and localization. A product and a buying process that only work in English exclude large parts of a market that a research report happily counts as addressable.
• Compliance and procurement. Regulated buyers need certifications, data residency, security reviews. If you cannot pass those gates yet, that revenue is real but it is not yours to serve this year.
• Pricing. There is a floor below which a deal costs you more to win and support than it returns. Accounts under that floor are demand, but serving them loses money.

Run those filters and the number that survives is your SAM. It is smaller than the headline TAM, and that is the point. A SAM that comes out nearly as large as your TAM is a warning sign, not a strength, and we will get to why.

Getting from TAM to SAM

The move from total addressable market to serviceable addressable market is subtraction. You start with everyone who has the problem and you take away the ones you cannot reach or cannot close.

Say your TAM is every B2B company in Europe with more than 50 employees that runs a sales team, and there are, for the sake of argument, 900,000 of them. Now apply the filters. Your product only supports HubSpot as the CRM, which cuts you to the roughly third of that base running HubSpot. You sell in English, German and French, which removes the Nordic and Southern European accounts you cannot support properly. Your pricing assumes a company with real revenue-operations spend, which pushes out the smallest firms in the count. Each filter is defensible on its own, and each one shrinks the number. What you are left with, maybe 120,000 companies, is a SAM you can point a sales plan at.

The discipline is naming every filter and being willing to defend it in a room. When someone challenges the SAM, you should be able to say which cut removed which companies and why. If you cannot, you do not have a SAM. You have a smaller-looking TAM.

Top-down vs bottom-up

There are two honest ways to size a SAM, and doing both is how you catch your own errors.

Top-down starts from the big number and filters down, the way the example above works. You take an industry-wide figure and apply percentages: this share runs the right tech stack, this share sits in your regions, this share is the right size. It is fast and it is directional. The risk is that every percentage is an estimate, and estimates stacked on estimates drift far from reality without anyone noticing.

Bottom-up builds from the unit. You count actual accounts that match your criteria, or you take your average contract value and multiply it by the realistic number of customers you could serve. If you know a fitting account pays you roughly 18,000 a year and you can identify 120,000 accounts that fit, your bottom-up SAM has a revenue figure attached that came from something you can observe. It takes longer and it forces you to define the account list, which is exactly why it is more trustworthy.

When the two methods land near each other, you can believe the number. When they diverge by an order of magnitude, one of your assumptions is wrong, and finding out which one is more valuable than the sizing itself. We tend to build the bottom-up version first with clients, because it drags every soft assumption into the light, then sanity-check it top-down.

SAM vs TAM

TAM is the whole demand for the problem you solve, regardless of whether you can reach it. SAM is the portion of that demand your current business can serve. The difference is not scale, it is reachability. TAM includes the buyer in a country you do not sell to, the enterprise you are not ready to support, the company on a CRM you do not integrate with. SAM excludes all of them because, today, you cannot serve them.

The most common mistake we see is a SAM that is really just TAM in a smaller font. Someone takes the industry number, lops off a round percentage that feels conservative, and calls the result the serviceable market. There are no named filters behind it, no account list, no reason the cut is 60 percent rather than 30. That is a TAM wearing a SAM label, and it falls apart the first time an investor or a board member asks how you got there.

A real SAM survives that question because every reduction traces to a boundary of your actual business. TAM answers how big the opportunity is in principle. SAM answers how much of it you are built to capture now. Below SAM sits the serviceable obtainable market, the share you can realistically win given your capacity and competition, which is a separate calculation again.

SAM should mirror your ICP

Here is a test worth running. Show your SAM definition to a rep who has been closing deals for a year, and watch their face. If the companies inside it are the ones they already recognize as good-fit accounts, your SAM is grounded. If the SAM includes segments they know never convert, or excludes the accounts they win most often, the number is describing a market you do not actually sell to.

SAM and your ideal customer profile are two views of the same thing. The ICP describes the company that succeeds with you and why. The SAM counts how many of those companies exist within your serving boundaries. When they line up, market sizing and account selection reinforce each other: the SAM tells you how big the well-fit market is, and the ICP tells you which specific accounts inside it to go after first. When they contradict each other, one of them is fiction, and it is usually the SAM, because ICPs get pressure-tested in real deals while SAMs get built once for a slide and never revisited.

The practical fix is to build the SAM from the same criteria that define the ICP, then keep both current. A segment that looked large in last year's sizing and never produced a closed-won deal should come out of the SAM this year. If you are working through the account-level version of this, our note on TAM mapping covers how to turn these market boundaries into a named list your sales team can actually work, which is where a defensible SAM stops being a slide and starts being useful.

Common questions