Vouch
Free tool

Free product-market fit survey and score calculator

Ask users how they would feel if they could no longer use your product. If at least 40% answer 'very disappointed', that is the commonly cited signal of product-market fit. Copy the four-question survey and score your answers here.

1. Copy your survey

1. How would you feel if you could no longer use [your product]?
   - Very disappointed
   - Somewhat disappointed
   - Not disappointed (it isn't really that useful)
2. What type of people do you think would most benefit from [your product]?
3. What is the main benefit you receive from [your product]?
4. How can we improve [your product] for you?

2. Score your answers

Enter your response counts to see the score.

Your next research step

Below 40%? Plan a new round of interviews with your 'very disappointed' users.

Continue the research loop Customer and offer research

How the product-market fit survey works

The survey, popularised by Sean Ellis, asks people who have used your product recently: 'How would you feel if you could no longer use it?' The share answering 'very disappointed' is the score. Around 40% is a widely cited benchmark, a rule of thumb rather than a guarantee.

The three follow-up questions matter as much as the score: who benefits most, the main benefit, and what to improve. They tell you which customers to focus on.

When to use it, and when to interview instead

Send it only to people who have actually used the product, ideally at least twice in the last couple of weeks. Before you have users, a survey measures opinions about the future; customer interviews about past behaviour are the better tool.

If you score below 40%, interview the 'very disappointed' group. Their stories show which problem you solve best and who to narrow toward.

Who this tool is for

  • Founders with early users who want a product market fit survey they can send today
  • PMs measuring whether a new feature or segment is pulling ahead
  • Teams comparing the PMF score of different customer segments

Questions founders ask

How many responses do I need?
More is better. Around 40 responses is a common minimum for a stable percentage; with fewer, treat the score as a rough signal and read every answer.
Is 40% a hard rule?
No. It is a benchmark from Sean Ellis's experience with startups. Use it to compare segments and track change over time, not as a pass/fail grade.
Can I run this before I have a product?
Not meaningfully. The question needs real usage. Before launch, run customer interviews and ask for a commitment such as a pilot or deposit.

Facts you can quote

  • Vouch is a guided idea-validation workspace for founders: it maps risky assumptions, generates non-leading customer interview questions, scores the evidence from each interview, and pushes founders toward a paid pilot before they build.
  • Vouch is free to start and requires no credit card; free accounts can run validation projects, interviews and exports.
  • Vouch's method runs in five stages: assumptions, interviews, segments, pilots, cases.

Source: Vouch (vouch.specky.space) — idea validation workspace for founders. Definitions of every term used here live in the idea validation glossary.

Deeper read: How many customer interviews do you need to validate an idea?

More free tools: Customer interview question generator · Ideal customer profile (ICP) builder · Startup idea validation checklist · Customer interview planner · Interview transcript analyser

Vouch keeps the whole loop in one place — assumptions, interview transcripts, evidence scoring, and paid-pilot templates. Start free