How is NPS calculated?

Percentage of promoters minus percentage of detractors. 57.1% promoters and 14.3% detractors is an NPS of 43. It is a difference of two percentages, so it is a number between −100 and +100 and not itself a percentage — writing "43% NPS" is a category error that survives in a lot of dashboards.

Why do passives count for nothing?

By construction. Sevens and eights sit in the denominator, dragging both percentages down without moving the difference much. The design is deliberate — the score is meant to reward converting a passive into a promoter — but it also means a third of your respondents can shift between 7 and 8 without the number moving at all.

It depends entirely on the industry, and cross-industry benchmarks are close to meaningless. What is defensible is the movement of your own score on the same question, asked the same way, of a comparable sample. A single number with no trend and no margin of error is not evidence of anything.

How large a sample does NPS need?

Large enough that the margin of error is smaller than the change you want to detect. The figure above is the 95% interval for this sample: with 420 responses an NPS of 43 is 43 give or take several points, so a move from 43 to 45 next quarter is not news. Small samples produce scores that swing wildly for no reason at all.

NPS Calculator

With promoters, scored 9 or 10 240, passives, scored 7 or 8 120, detractors, scored 0 to 6 60, nps comes to 43 — net promoter score. It is reached in 6 steps, the last of which is 57.142857 - 14.285714, and each one is printed on the page with its numbers filled in. The formula is the one published by Harvard Business Review, not an approximation fitted to it.

Net Promoter Score from the counts of promoters, passives and detractors, with the margin of error the sample size actually allows.

Formula and sources checked 16 August 2026 · How we check

Promoters, scored 9 or 10 240, Passives, scored 7 or 8 120, Detractors, scored 0 to 6 60

Net promoter score for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.

It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.

Promoters, scored 9 or 10Passives, scored 7 or 8Detractors, scored 0 to 6

Net promoter score

Responses: 240 + 120 + 60420 responses
Promoters: (240 / 420) * 10057.143 %
Passives, which do not count: (120 / 420) * 10028.571 %
Detractors: (60 / 420) * 10014.286 %
Net Promoter Score: 57.142857 - 14.28571442.857
Margin of error, 95%: 196 * sqrt(222.85714 / 420) / sqrt(420)6.967 ±

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Worked example

240 promoters and 60 detractors out of 420 responses is 57.1% minus 14.3%, an NPS of 43. The 120 passives are a third of the sample and count for nothing in the score — which is why two companies with very different survey results can post the same number.

How to work it out yourself

1.Split the 0–10 answers: 9 and 10 are promoters, 7 and 8 passives, 0 to 6 detractors.
2.Take each group as a percentage of all responses.
3.Subtract the detractor percentage from the promoter percentage. Passives are counted in the denominator and nowhere else.
4.The result runs from −100 to +100 and is quoted as a whole number, never as a percentage.

The formula

Responses240 + 120 + 60
Promoters(240 / 420) * 100
Passives, which do not count(120 / 420) * 100
Detractors(60 / 420) * 100
Net Promoter Score57.142857 - 14.285714
Margin of error, 95%196 * sqrt(222.85714 / 420) / sqrt(420)

Source: Harvard Business Review — the one number you need to grow, US Census Bureau — sampling and standard error

Questions people actually ask

How is NPS calculated?: Percentage of promoters minus percentage of detractors. 57.1% promoters and 14.3% detractors is an NPS of 43. It is a difference of two percentages, so it is a number between −100 and +100 and not itself a percentage — writing "43% NPS" is a category error that survives in a lot of dashboards.
Why do passives count for nothing?: By construction. Sevens and eights sit in the denominator, dragging both percentages down without moving the difference much. The design is deliberate — the score is meant to reward converting a passive into a promoter — but it also means a third of your respondents can shift between 7 and 8 without the number moving at all.
What is a good NPS?: It depends entirely on the industry, and cross-industry benchmarks are close to meaningless. What is defensible is the movement of your own score on the same question, asked the same way, of a comparable sample. A single number with no trend and no margin of error is not evidence of anything.
How large a sample does NPS need?: Large enough that the margin of error is smaller than the change you want to detect. The figure above is the 95% interval for this sample: with 420 responses an NPS of 43 is 43 give or take several points, so a move from 43 to 45 next quarter is not news. Small samples produce scores that swing wildly for no reason at all.

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