How to calculate NPS
Net Promoter Score is calculated by subtracting the percentage of detractors from the percentage of promoters:
NPS = % promoters − % detractors
Respondents answer one question — "How likely are you to recommend us to a friend or colleague?" — on a 0-10 scale, and fall into three groups:
- Promoters (9-10): enthusiastic fans who will keep buying and refer others.
- Passives (7-8): satisfied but unenthusiastic. They don't count toward your score, but they can be swayed either way.
- Detractors (0-6): unhappy customers who can damage your brand through negative word of mouth.
The result is a number between −100 (everyone is a detractor) and +100 (everyone is a promoter). Say you surveyed 200 customers: 120 scored 9-10, 50 scored 7-8, and 30 scored 0-6. That's 60% promoters and 15% detractors, so your NPS is 45.
What is a good NPS score?
Anything above 0 means you have more promoters than detractors. As a rule of thumb:
| NPS range | Interpretation |
|---|---|
| Above 80 | World class — rare, even among beloved brands |
| 50 to 80 | Excellent — customers actively love your product |
| 20 to 50 | Favorable — a healthy base of fans |
| 0 to 20 | Needs improvement — positive, but fragile |
| Below 0 | At risk — detractors outnumber promoters |
Benchmarks vary a lot by industry. Software companies often average around 30-40, while industries with captive customers (telecom, insurance) can average near zero. The most useful comparison is your own score over time: run the same NPS survey every quarter and watch the trend, not just the number.
Why NPS matters
NPS became the standard loyalty metric because it correlates with growth: promoters buy more, stay longer, and refer new customers. It's also disarmingly simple. One question means high response rates, and a single number means everyone in the company understands whether things are getting better or worse.
The score alone doesn't tell you why, though. That's why most NPS surveys pair the 0-10 question with one open-ended follow-up: "What's the main reason for your score?" The score gives you the trend; the comments give you the roadmap. If you're building your first NPS survey, our guide on how to run an NPS survey walks through question wording, timing, and segmentation.
Tips for reliable NPS results
- Survey enough people. With 20 responses, one unhappy customer swings your score by 5 points. Use our sample size calculator to know how many responses you need.
- Keep the question standard. The 0-10 "how likely are you to recommend" wording is what makes your score comparable to benchmarks.
- Ask everyone, not just happy customers. Surveying only engaged users inflates the score and hides problems.
- Follow up with detractors quickly. A response within days can turn a detractor into a promoter — and at minimum it shows you listen.
- Track the segments, not just the score. An NPS of 20 from 60% promoters and 40% detractors is a very different business than 30% promoters and 10% detractors.
Measure NPS with a survey people actually finish
Your NPS is only as good as your response rate, and response rate depends on the survey itself. Fomr lets you build a one-question NPS survey with a 0-10 scale field, an optional follow-up question, and a design that matches your brand — free, with unlimited responses. Share it by link, embed it on your site, or send it by email, then bring your promoter and detractor counts back here.