How to find product-market fit: signals to watch and the conversations that help

You find product-market fit by choosing a problem that a specific group of customers urgently needs solved, putting a simple product in front of them quickly, and then narrowing, through usage data and conversations, to the customers who would be upset to lose it, until demand from that group starts pulling the product forward. The work is mostly learning who needs it most and why, and changing the product or the market until the answer is clear.

Marc Andreessen, who popularized the term in a 2007 essay, defined it as "being in a good market with a product that can satisfy that market." This page covers the signals that tell you whether you have it and a practical loop for getting there through customer conversations.

What product-market fit looks like, and what it does not

Andreessen's description is still the most quoted. When it is not happening, customers are not quite getting value, word of mouth is not spreading, usage is not growing fast, the sales cycle takes too long and lots of deals never close. When it is happening, customers buy as fast as you can deliver, usage grows as fast as you can support it, and you are hiring sales and support staff as fast as you can.

Michael Seibel of Y Combinator adds a warning: many founders believe they have product-market fit when they have not, then hire, raise their burn rate and optimize a product before they have found what needs to be built. His test is whether you are overwhelmed with usage from happy, loyal and ideally paying customers. Headcount and a large funding round are not evidence.

Those descriptions are useful once fit has arrived. Before that, you need earlier signals.

Earlier signals to watch

None of these proves fit on its own. Together they tell you whether you are getting closer.

• Retention that levels off. Track what share of each group of new customers is still active after one, two and three months. If the curve keeps falling toward zero, people try the product and leave. If it flattens for some group, that group is getting lasting value. Look at which customers make up the flat part.
• The product-market fit survey. Ask recent active users how they would feel if they could no longer use the product. Sean Ellis, according to Rahul Vohra's account in First Round Review, benchmarked nearly a hundred startups and found that those struggling to grow almost always had fewer than 40% answer "very disappointed." Treat 40% as a practitioner's rule of thumb. Our guide to the product-market fit survey covers how to run and read it.
• Pull you did not create. Customers refer others without being asked, request more seats, or complain loudly when something breaks. People who would barely notice an outage are not relying on you.
• Sales that get easier. In B2B, a shorter path from first call to signed contract and fewer deals stalling are signs that the problem is urgent for the buyer. Andreessen lists long sales cycles and deals that never close as signs fit is missing.

Start from the problem

Seibel's advice on finding fit is to focus on the market first. He writes that founders hold too tightly to solutions and too loosely to problems, and that the first version of a solution is usually wrong; you find the product that fits by launching, talking to customers and iterating. He looks for problems so pressing that people will try a half-built first version, and says that in a good market a minimum viable product is enough to get the first customers in the door and giving feedback.

In practice, that means your early conversations should be about the problem, not your product. Ask people in the market to walk you through the last time the problem came up: what they did, how long it took, what it cost, and what they use now. Signs of an urgent problem include a workaround they built themselves, money or staff time already spent on it, and a recent, specific story rather than a general complaint. Customer discovery covers this stage in depth, and problem interviews vs. solution interviews helps you tell which kind of conversation you need.

Narrow to the customers who need it most

Early products usually attract a mix of customers, and averaging their feedback hides the group that loves you. Vohra describes narrowing Superhuman's survey results to the types of users who showed up among those answering "very disappointed," describing that group in detail, and focusing the product on them. By his account, narrowing the analysis this way raised the share of very disappointed users from 22% to 33% before any product changes. That is one company's report, but the method works at any size: find who gets the most value and learn what they have in common.

Conversations are how you learn what they have in common. Talk separately to your most engaged customers and to customers who tried the product and drifted away. Compare their jobs, company types, the problem that brought them in and what they used before. The differences usually point to the segment to focus on and the gaps that keep others from sticking.

A monthly loop, with an example

Suppose you have built software that checks patients' dental insurance before appointments, and 12 dental offices are using it. This example is hypothetical.

1. Measure. After eight weeks, 5 of the 12 offices use it every day, 4 use it occasionally and 3 have stopped. Daily use: 5 ÷ 12 = 42%.
2. Talk. Interview the office managers at the 5 daily users and at the 3 that stopped. Ask each to walk through yesterday's check-ins.
3. Find the difference. Suppose all 5 daily users are multi-location groups where one person verifies insurance for several offices, and the 3 that stopped are single-dentist practices where the front desk verifies coverage between other tasks.
4. Decide. Focus the next month on multi-location groups: find more of them, and fix what the 4 occasional users say holds them back if they fit that profile.
5. Repeat. Re-measure with the next group of offices and see whether daily use rises.

If several rounds pass and no group shows urgency, change something bigger. Andreessen's advice for the period before fit is to do whatever is required, including rewriting the product or moving to a different market.

Your next step

Write down which group of customers uses your product most and what you think they have in common, then book conversations with five of them and five who stopped. If you need people in the market who are not yet your users, such as office managers at dental groups, search for people by describing their role, or start from the operations professionals in dental services directory page. Instant Expert finds people whose work matches your question. You review them, it sends the invitations, and you pay for each call that gets booked.