Guide

How Many Companies Actually Fit Your ICP? A 15-Minute TAM Estimate

A practical way for a small sales team to estimate how many companies actually match their ICP, without a market research firm or a VC-deck TAM slide.

"How big is our market" and "how many companies could we actually call this quarter" are different questions, and most TAM exercises answer the first one in a way that's useless for the second. Here's a back-of-envelope version aimed at the second question, doable in about fifteen minutes with things you can look up yourself.

Step 1: pin down your ICP criteria as filters, not adjectives

You need: a specific industry classification (not "tech", an actual NACE/SIC/NAICS code or two), an employee or revenue range, and a geography. If you haven't written this down precisely yet, see Ideal Customer Profile first, this estimate is only as good as the filter behind it.

Step 2: find the base count

Business registries (most EU countries publish these, often free or cheap to query), LinkedIn's company search with industry and size filters, or a quick search of any B2B company database will give you a rough count of companies matching industry + size + geography. Don't aim for precision here, aim for order of magnitude: is it 200 companies or 20,000?

Step 3: apply a realistic reachability discount

Not every company in that count is actually reachable or relevant: some are dormant, some are already customers or in an existing pipeline, some are technically the right size but the wrong sub-segment. A rough discount of 30-50% off the base count is a reasonable starting assumption until you have real data to replace it.

StepExample
Base count (industry + size + geography)1,400 companies
Apply ~40% reachability discount≈ 840 companies
This is your rough SAMSee TAM vs SAM vs ICP

Step 4: this number is your ceiling, not your list

840 companies is the pool you could theoretically pursue, it's not a prioritized list. The next step is scoring each one against your full ICP (industry match is only one filter of several) to find which specific companies are worth calling first, that's firmographic scoring, and you can try a simplified version instantly with the ICP Fit Score Calculator.

Why this matters even at a small scale

A team that doesn't know its rough addressable pool tends to do one of two things badly: assume the market is infinite and never systematically work through it, or assume it's exhausted after a few dozen calls and panic. Fifteen minutes of estimation fixes both, and gives you a real denominator for "how much of our actual market have we covered so far."

See this against your own ICP

Bring your criteria to a live call. We'll run a real scoring pass while you watch, not a slide deck.

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