What is an ideal customer profile (ICP)?

Written by Madalena Rugeroni, founder of Mazo · Updated 15 September 2026

An ideal customer profile (ICP) describes the type of company that gets the most value from your product and is most valuable to you: the customers who buy fastest, stay longest and expand most. In B2B SaaS it combines company traits with the situation or trigger event that makes a company ready to buy now.

What goes into an ICP

Winning by Design's version has four parts:

Ideal company: type, size, industry, revenue and tech stack.
Ideal personas: the user and the buyer, each with their role, jobs to be done, KPIs, frustrations and dream outcome.
Trigger events: observable signs a company is in the market now — new funding, a leadership hire, job posts that match your use case.
Anti-ICP: who not to chase, written down.

An ICP describes the account; a buyer persona describes the people inside it.

Worked example

A fictional accounts-payable tool writes its ICP after its first 15 customers:

Company: accounting firms with 10–50 staff that serve small businesses and already use cloud accounting software.
Buyer: the managing partner; user: the bookkeeping lead, who spends two days a month chasing supplier invoices.
Trigger: the firm has just taken on a batch of new clients, or lost a bookkeeper.
Anti-ICP: firms under 5 staff (too little volume) and firms on desktop accounting software (can't integrate).

The trigger is the part a demographic ICP would miss — and the part that tells outbound when to reach out.

Why the ICP matters from €0 to €1M ARR

Pre-revenue to 10 customers: your ICP is a hypothesis. Test it with Cindy Alvarez's interview rules from Lean Customer Development: ask about past behaviour, never future intent, and listen for workarounds and money already spent.
10 to 50 customers: stop guessing. April Dunford's approach in Obviously Awesome is to derive the ICP from your best-fit customers — those who closed fastest, retained best and expanded most — and find what they share.
50 customers to €1M ARR: enforce it. Tailor demos, qualify out the anti-ICP in sales, and watch churn: the same profile churning repeatedly means it was never your ICP.

Mazo's rule of thumb: under 10 customers, treat your ICP as a hypothesis. Interview 5 people who share one profile. If the same pain comes up in all 5, build around it; if it doesn't, change the profile before you interview more. From 10 customers on, define your ICP from the customers who bought fastest and stayed longest. No workaround or spend today usually means they're not your ICP.

Common ICP mistakes

Demographics only. "B2B SaaS, 10–200 employees" describes thousands of companies with nothing in common.
An ICP that isn't enforced. Defined in a doc, ignored by the website, the demo and the outbound list.
No anti-ICP. Without one, every inbound lead looks worth a call.
Interviewing scattered profiles. Fifteen interviews across different profiles is noise; five within one is signal.

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FAQ

What is the difference between an ICP and a buyer persona?

An ICP describes the ideal company to sell to: its size, industry, situation and triggers. A buyer persona describes the people inside that company, such as the user and the budget holder, and what each of them cares about.

How do I define an ICP with no customers?

Write a hypothesis for one tight profile and interview about five people who fit it, asking about the last time they dealt with the problem. If all five describe the same pain and a workaround they already pay for, you have a working ICP.

Can a startup have more than one ICP?

It can later, but before €1M ARR one ICP is usually right. Every extra profile splits your positioning, your outbound list and your product roadmap.

Who wrote this

Madalena Rugeroni built Mazo. She's an ex-Googler, a startup advisor and investor, and runs a portfolio of internet companies. Before that, as Head of Growth at Amplemarket, she scaled a B2B SaaS to $10M ARR. LinkedIn

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Further reading. Operators and books referenced: Winning by Design, April Dunford (Obviously Awesome), Cindy Alvarez (Lean Customer Development). These are published methodologies credited to their authors; Mazo is not affiliated with or endorsed by them.