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"How likely are you to recommend us to a friend or colleague?" on a scale from 0 to 10.
Free NPS calculator. Your score, and how sure you can be of it.
Net Promoter Score
Enter how many promoters, passives and detractors you have, or paste the scores.
Net Promoter Score is the share of promoters (9 or 10) minus the share of detractors (0 to 6), from -100 to +100. Enter your counts or paste the raw answers above. Unlike other calculators, this one also shows the margin of error, how many responses you need, and whether a change since last period is real. Nothing is sent or stored.
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- Margin of error included
Last updated:
How do you calculate NPS?
1 2 Sort the answers
9 and 10 are promoters, 7 and 8 are passives, 0 to 6 are detractors.
3 Subtract
% promoters minus % detractors. 50 promoters, 30 passives and 20 detractors out of 100 give 50% minus 20% = NPS 30.
Why the margin of error matters
An NPS from a survey is an estimate. With 100 responses and a score of 30, the real score of all your customers is most likely anywhere between about 15 and 45. That is why a score can jump 10 points from one month to the next without anything changing.
The calculator uses the standard formula for a score made of two shares: the variance is (promoter share + detractor share − (promoter share − detractor share)²) divided by the number of responses, and the 95% margin is 1.96 times its square root. Below 30 responses the approximation is weak, so the tool says the score is rough instead of printing a precise range.
Comparing two periods works the same way: the change is only likely to be real when it is larger than the combined margin of both periods. Use the "compare" option above before you celebrate or worry about a move.
How many responses do you need?
For a margin of ±5 points at a typical mix of answers (about half promoters, a quarter passives, a quarter detractors).
| Margin of error | Responses needed |
|---|---|
| ±15 points | about 120 |
| ±10 points | about 260 |
| ±5 points | about 1,050 |
| ±3 points | about 2,900 |
Calculated with the formula above for 50% promoters and 25% detractors. Your own mix changes the numbers; the calculator uses it.
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What to do with detractors
A low score is usually about one moment: a question that waited, a delivery nobody explained, a problem with no follow-up.
- Reply to every detractor personally, and ask what would have changed their score.
- Group what they say. The same two or three reasons usually come back.
- Answer the common questions before they turn into complaints: SimplyBoost replies in seconds on your website, WhatsApp and Instagram, day and night.
Questions about NPS
NPS = % promoters − % detractors. Promoters answer 9 or 10, passives 7 or 8, detractors 0 to 6. Passives count in the total but not in the subtraction. The result runs from -100 to +100.
Yes. When there are more detractors than promoters the score is below zero, down to -100 when every answer is 6 or lower.
It depends on your industry, your customers and how you ask, and published averages differ a lot between sources. The most useful comparison is with your own earlier scores, using the comparison above so you know whether a change is larger than chance.
At least 30 for a rough score. For a margin of ±10 points, about 260 responses at a typical mix; for ±5 points, about 1,050. The calculator works it out for your own answers.
Only if it is larger than the margin of error of both periods together. Tick "compare with an earlier period", enter the earlier counts, and the calculator tells you whether the change is likely real or may be chance.
NPS asks how likely someone is to recommend you, so it measures the relationship. CSAT asks how satisfied someone was with one interaction, such as a support conversation. Use the CSAT calculator for that.
No. The calculation runs in your browser and nothing is sent to us. Net Promoter, Net Promoter Score and NPS are registered trademarks of Bain & Company, Satmetrix Systems and Fred Reichheld.
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