TL;DR

Product-market fit (PMF) is the degree to which a product satisfies a strong market demand. It is the most important milestone for an early-stage startup. PMF is not binary — it exists on a spectrum and can be measured through retention curves, the Sean Ellis test, NPS, and revenue growth rate.

The Sean Ellis Test

Question: "How would you feel if you could no longer use [product]?"

Benchmark: If 40%+ say "very disappointed," you have PMF. Below 40% means iterate.

How to use: Survey your most active users (used product at least twice in last 30 days).

Retention Curves

Plot the percentage of users still active N days/weeks/months after first use.

PMF signal: The retention curve flattens at a meaningful level.

  • Consumer: Flatten at 20–40%+ = PMF
  • B2B: Flatten at 60–80%+ = PMF

If the curve goes to zero, you do not have PMF.

Revenue-Based PMF Signals

  • NRR > 100%: Existing customers expanding faster than they churn
  • Organic growth > 20% of new customers: Word-of-mouth indicates love
  • Sales cycle shortening: Customers need less convincing
  • Churn rate declining: Improving retention over time

The PMF Score Framework

SignalWeight
Sean Ellis test (% very disappointed)30%
D30 retention rate25%
NRR20%
Organic growth %15%
NPS10%
  • Weighted PMF score greater than 3.5: Strong PMF
  • 2.5–3.5: Emerging PMF
  • less than 2.5: No PMF

    • Key Takeaways

    Key Takeaways
    • PMF is the most important milestone for an early-stage startup.
    • The Sean Ellis test: 40%+ "very disappointed" = PMF signal.
    • Retention curves that flatten at a meaningful level are the most reliable PMF indicator.
    • NRR greater than 100% and organic growth greater than 20% are strong B2B PMF signals.
    • PMF is a spectrum — measure it continuously, not just once.
product-market fitPMFretentionSean Ellis testgrowth metricsstartup advisoryventure capitalNorth AmericaQueretaro MexicoHerbert MarchettiAgentivo Capital

Related Articles