NPS calculator
Net promoter score is the percentage of promoters (9–10) minus the percentage of detractors (0–6), on a scale from −100 to +100. Passives (7–8) count towards the total you divide by but towards neither side.
NPS, step by step
Discarding the passives is deliberate and it is what makes NPS volatile: a score built from the two tails moves far more than an average would. On a hundred responses, four people changing their minds moves the score by eight points, which is why month-to-month movement on a small sample is almost always noise.
The number is nearly useless without the free-text answer to "why?". The score tells you whether something changed; the comments tell you what, and they are the only part of an NPS survey that produces an action.
Where this number misleads you
NPS has a response-bias problem that no amount of arithmetic fixes: the people who answer are not a random sample of your users, and asking inside the product after a successful action produces a very different score from asking by email a month later. Keep the timing, the wording and the channel identical, or you are measuring your survey rather than your customers.
Questions people ask
How is NPS calculated?
Divide promoters (scores of 9–10) by total responses, divide detractors (0–6) by total responses, and subtract the second percentage from the first. Passives (7–8) are counted in the total but in neither group. The result runs from −100 to +100 and is reported as a number, not a percentage.
What is a good NPS?
Above 0 means more promoters than detractors; above 50 is generally considered excellent. Industry averages vary enormously, so the useful comparison is against your own previous score with the same question asked the same way at the same point in the customer journey.
How many responses does NPS need?
Several hundred before period-to-period movement means much. Because the score drops the middle of the scale, it is unusually sensitive to small samples: under about 100 responses, a handful of changed minds moves it by ten points, which is easy to mistake for a trend.
When one number is not the job
This page works out one number. PikoPM’s Survey asks the question, hosts it, and counts the answers, so the number comes from your customers rather than a guess.
Open Survey — it needs an account, and the Free plan covers it.