A marketplace doesn't have one product-market fit. It has two — one for buyers, one for sellers — and they can be in completely different places. A blended 40% can hide a thriving demand side propped up against a supply side that's about to churn out. So the benchmark is the same; the unit of measurement is different.
Is the PMF benchmark different for marketplaces? No — it's still 40%. But you run the survey twice: once per side.
Who counts as an engaged user in a marketplace
On both sides, engagement means a completed transaction, recently. A buyer who browsed but never bought, or a seller who listed but never sold, hasn't experienced the marketplace's core promise — liquidity. Survey people who've actually transacted, and survey each side separately.
Measure the side you're constrained on
Most marketplaces are bottlenecked on one side — usually supply. That's the side whose PMF score you should watch most closely, because it's the one that will break first. A 60% score among buyers is worthless if sellers are at 20% and leaving. The constrained side is your growth ceiling.
What Airbnb did
Airbnb's early numbers were flat because the supply side wasn't working — listings had terrible photos and weren't converting. The founders didn't run a survey to learn this; they flew to New York and fixed it by hand, shooting professional photos themselves. Bookings climbed. The lesson translates directly: when one side of your marketplace is dragging, that's where your fit problem is, and that's the side to measure and obsess over.
See where you land against 40%
The free PMF score calculator runs the Sean Ellis survey on your users and shows your score against the benchmark — no signup.
Calculate your PMF score → Built on the Sean Ellis 40% method.How to measure PMF in a marketplace
- Run the survey twice. Once for buyers who bought, once for sellers who sold. Keep the scores separate.
- Define engagement as a completed transaction. Browsing isn't experiencing the product; transacting is.
- Prioritize the constrained side. Your overall fit is capped by whichever side scores lower.
- Read the "why" for liquidity language. "I can always find what I need" (demand) and "I get reliable buyers" (supply) are the value props you want to hear.
One marketplace, two scores. Blend them and you'll feel fine right up until the weaker side collapses. Measure them apart and you'll see the problem while there's still time to fix it.
Measure your fit, find your ICP, track the trend
PMFtracker runs the Sean Ellis survey on your engaged users, scores you against the 40% benchmark, surfaces your ICP from the open-ended answers, and tracks the trend over time.
Start measuring free → Set up in 5 minutes · No credit card required
