What is product-market fit?

Product-market fit is the point at which a product satisfies a real market need well enough that customers buy it without extensive persuasion, use it consistently, and refer others to it without being asked. Before product-market fit, every customer requires significant effort to acquire and often churns quickly. After it, growth has a pull to it — customers come back, retention is strong, and the sales motion gets easier over time rather than harder.

How do you know if you have product-market fit?

The most cited signal: Sean Ellis's 40% rule. Survey active customers with the question "How would you feel if you could no longer use this product?" If more than 40% say "very disappointed," you likely have product-market fit. Below 40%, you don't — at least not broadly. Other indicators: monthly churn below 2%, NPS above 40, customers who proactively refer others without incentives, and a sales cycle that's getting shorter as the market develops awareness of the category.

What does product-market fit actually feel like?

Before PMF, every deal requires the founder to personally carry it. Every customer has a different set of objections. Churn is unpredictable and often surprising. The team spends significant time re-explaining the value proposition even to existing customers. After PMF, the product sells to people who already understand why they need it. Objections are consistent and manageable. Retention is strong. The founder stops feeling like they're pushing every deal across the finish line.

Can you have partial product-market fit?

Yes. PMF is not binary — it exists on a spectrum and within specific segments. A product can have strong PMF with founder-led SaaS companies with 20–80 employees and weak PMF with enterprise companies over 500. The common mistake is declaring PMF based on a handful of strong early customers without confirming the fit generalises to the broader segment. Partial fit in a narrow segment is the right foundation to build on. It becomes a problem when teams scale GTM before confirming the fit holds at scale.

What is the difference between product-market fit and go-to-market fit?

PMF means the right product for the right market — customers want what you built. Go-to-market fit means the right channel and motion for reaching and closing those customers efficiently. A company can have PMF (the product is genuinely valued by a segment) and poor GTM fit (they can't find those customers at acceptable CAC). Both are required for sustainable growth. PMF is necessary but not sufficient — GTM fit is what turns a good product into a growing business.