How to measure product–market fit

Product–market fit is often described as something you recognise when you reach it. That is of limited use when you are deciding what to build next. Fortunately, it can be measured — and the results can guide clear, practical product decisions.

Signs you have not reached it yet

The absence of fit usually shows before it can be defined. Growth depends heavily on outbound effort, users sign up but do not return, feedback is positive but not enthusiastic, and the roadmap fills with features in the hope that one will make the difference.

In this situation, adding features rarely solves the problem. A clearer understanding of users does.

A single, practical measure

Marketer Sean Ellis popularised a simple survey for active users: “How would you feel if you could no longer use this product?” The answers: very disappointed, somewhat disappointed or not disappointed.

His benchmark suggests that when around 40% of users answer “very disappointed”, a product is usually close to fit. Below that level, the survey responses indicate where to focus.

Survey the right users

The survey only works if you send it to the right users. Ask people who've genuinely experienced the product — typically those who've used the core feature a few times recently. New sign-ups have not yet formed a view, and users who left long ago are describing an earlier version of the product.

Keep the survey short. Alongside the main question, ask who they think would benefit most, what main benefit they receive and how the product could be improved for them. These answers inform the analysis that follows.

“Build for the people who would be most disappointed to lose you — not for everyone.”

Understand your most engaged users

Users who would be very disappointed to lose the product are your most important segment. Understand who they are, which features they use most and what benefit they receive that alternatives do not provide.

Their responses often describe the market you are already serving well, which may differ from the one you originally targeted. That insight is valuable: it shows where to focus.

Turn the answers into a roadmap

Once you understand who values the product and why, prioritisation becomes clearer. We typically divide effort into two areas:

• Strengthen — improve what your most engaged users value most.
• Remove barriers — address what holds back users who value the same benefit but are not yet fully convinced.

It is equally important to deprioritise requests from users who would not miss the product. Focusing resources on the users who value it most is what moves the measure.

Track fit over time

Repeat the survey at regular intervals as new releases go out. Tracking the result over time provides an objective basis for prioritisation and gives the whole team a shared, measurable goal.

It also supports clearer conversations with investors, partners and internal teams — replacing general impressions with a measurable indicator of how much users value the product.

Further reading: How Superhuman Built an Engine to Find Product-Market Fit — Rahul Vohra, First Round Review