How to calculate NPS, and what to do with the number
Updated
Net Promoter Score is one question, three buckets, and one subtraction. The arithmetic takes a minute; the part most businesses get wrong is everything around it — how many answers you need before the number means anything, and the follow-up question that tells you why it moved.
The question
“How likely are you to recommend [business] to a friend or colleague?” answered on a scale from 0 (not at all likely) to 10 (extremely likely). Keep the wording and the 0–10 scale exactly: change either and your score is no longer comparable to anyone else’s, or to your own past results.
The formula
- Group every answer: 9–10 are promoters, 7–8 are passives, 0–6 are detractors.
- Work out the percentage of all respondents who are promoters, and the percentage who are detractors.
- NPS = % promoters − % detractors. Passives count toward the total but not in either percentage.
The result is a whole number from −100 (everyone a detractor) to +100 (everyone a promoter). It is written without a percent sign.
Run your first NPS survey today
Start from the NPS template, share it by link, QR code, or embed, and read the score and the reasons in one dashboard. Free for up to 5 surveys and 100 responses each — no credit card.
Get started for freeA worked example
| Group | Scores | Responses | Share |
|---|---|---|---|
| Promoters | 9–10 | 110 | 55% |
| Passives | 7–8 | 50 | 25% |
| Detractors | 0–6 | 40 | 20% |
| Total | 200 | 100% |
NPS = 55 − 20 = 35.
How many responses before it means anything
With 50 responses, each person is 2% of the total. If a single detractor had answered 9 instead of 6, promoters go up 2 points and detractors down 2 — and the NPS moves by 4. A swing of that size week to week is noise, not news.
- Compare periods of equal length with similar response counts.
- Watch the trend over several periods rather than reacting to one.
- Report the response count next to the score, always.
What is a good NPS?
Anything above zero means more promoters than detractors, but beyond that “good” depends heavily on industry and on how and when you ask. Published benchmarks use different panels and methods, so the most reliable comparison is your own score over time, measured the same way.
The follow-up question that makes it useful
A score tells you where you stand; it cannot tell you what to fix. Follow the 0–10 question with an open one — “What is the main reason for your score?” — and, if you can, ask detractors something more specific, such as what nearly stopped them buying. Twenty written reasons from detractors are usually worth more than the score itself.
NPS vs CSAT
| NPS | CSAT | |
|---|---|---|
| Measures | Overall loyalty to the business | Satisfaction with one interaction |
| Question | Likelihood to recommend, 0–10 | How satisfied were you, usually 1–5 |
| Score | % promoters − % detractors | Share of 4 and 5 answers |
| Best sent | Periodically, or some time after purchase | Right after the delivery, visit, or support contact |
Running NPS in Proterate Surveys
Start from the NPS template, add conditional logic so detractors are asked why while promoters are not handed the same wall of questions, and share it by link, QR code on a receipt or table card, or an embed on your site. Every channel feeds one dashboard of scores and trends over time, filterable by date range, so you can see whether a change actually moved the number.
Frequently asked
Is NPS a percentage?
No. It is the difference between two percentages, written as a whole number from −100 to +100 with no percent sign.
Why do passives not count?
They count in the total number of respondents, so they dilute both percentages, but they are not added or subtracted. More passives pulls the score toward zero.
Can I use a 1–5 scale for NPS?
Not if you want to call it NPS. The method is defined on 0–10; on a different scale the buckets no longer mean the same thing and the score is not comparable.
How often should I run an NPS survey?
Often enough to collect a meaningful number of responses per period, and at a consistent point in the customer relationship. Asking the same customer every week trains them to ignore it.