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Rahul Vohra: The Exact Method to Measure Product-Market Fit With a Number

By Rahul Vohra · Product · 1 min read

Ask your users: how would you feel if you could no longer use the product? Very disappointed, somewhat disappointed, or not disappointed. If 40% say very disappointed — you have product-market fit. Even Slack only hit 51%.

Key Points

Sean Ellis's method: one question — how would you feel if you could no longer use this product?
40% very disappointed = product-market fit. Benchmarked across hundreds of startups.
Slack hit 51% — only 10% above the threshold. Shows how hard it is to beat.

If more than 40% of your users would be very disappointed without your product, focus on growing. If less than 40%, you'll probably struggle to grow.

Finding a Definition

Vohra: I wanted a definition of product-market fit. A metric I could explain to the people working with me — that we didn't have it. And a methodology to optimize it. I searched high and low, read everything, spoke with all the experts.

Then I found Sean Ellis — the growth hacking guy. Before he coined the term 'growth hacker,' he ran early growth at Dropbox, LogMeIn, Eventbrite. During that period, he found a way to measure product-market fit.

I wanted a metric I could show the team — that we didn't have PMF. And a methodology to optimize it.

The 40% Threshold

Vohra: Simply ask your users: how would you feel if you could no longer use the product? Three options — very disappointed, somewhat disappointed, not disappointed.

The benchmark is 40% very disappointed. This has been benchmarked across hundreds of venture-backed startups. If more than 40% say very disappointed, focus on growing. If less than 40%, you'll probably struggle to grow.

40% very disappointed. That is the threshold. Benchmarked across hundreds of startups.

Even Slack Only Hit 51%

Vohra: Hiten Shah did a survey early in Slack's lifecycle — posed that very question to 731 people. 51% said they would be very disappointed without Slack. 51% is greater than 40%, so Slack has product-market fit.

But it shows just how hard it is to beat that benchmark. It's not like Slack has 60 or 70 or 80%. It's just 50%. Only 10% more than 40.

Slack hit 51%. Not 60, not 80. Just 51. Only 10% above the threshold.

Why Negative Framing Works

Vohra: If you ask people how they feel about a product with positive potential responses, it invites more bias. People are more likely to be polite. The negative framing gets to the heart of the matter — how necessary has your product become for people's lives?

It's somewhere between Paul Graham's question of 'do people want it?' and Sam Altman's question of 'do people talk about it?' This question is the third leg — do people need it? Would they feel sad without it?

Paul Graham: do people want it? Sam Altman: do they talk about it? This question: do they need it?