Net Promoter Score Calculator

NPS meaning, and the three groups behind one question

The net promoter score measures how willing your customers are to recommend you, and it rests on a single question: how likely are you to recommend us? Answers come on a 0-to-10 scale, and they sort people into three groups. Promoters (9–10) recommend you actively. Passives (7–8) are satisfied without being enthusiastic. Detractors (0–6) are unhappy and carry most of the negative word of mouth. The score runs from −100 to 100 and is a balance, not a percentage: it says how far advocates outweigh critics.

Passives in the denominator: how to calculate NPS honestly

NPS = (promoters ÷ responses × 100) − (detractors ÷ responses × 100)

The passives are missing from the formula on purpose, not by oversight. They belong to the total, which shrinks both shares — their votes dilute the result without pulling it either way. Drop them from the denominator and you are not measuring loyalty any more, you are flattering yourself.

Running the numbers on 100 survey responses

A survey returns 100 answers: 60 promoters, 25 passives, 15 detractors.

45 sits in the «very good» band, just short of the «excellent» line at 50. The interesting figure is the middle group: convert ten of those 25 passives into promoters and the score reaches 55 without a single new customer.

Culture moves it more than quality: what is a good NPS score?

Above 80 counts as world class, and very few get there. This scale is deliberately industry-agnostic, because scores swing enormously between sectors and between countries — German-speaking respondents rate notoriously more conservatively than American ones, which means the same product can post two very different numbers. Comparing against someone else's figure therefore misleads more often than it helps. What carries information is the direction your own score moves across several periods.

The one number it does not actually predict

The score is often sold as a growth forecast — the original book was called «The One Number You Need to Grow». That claim is academically contested: studies found no evidence that the recommendation question predicts growth better than other loyalty questions do. This does not make the metric worthless. It is quick to collect and universally understood, which is rare. But it is a sentiment signal, not a forecast, and tying bonuses to it reliably produces better scores rather than happier customers. For a harder check, measure behaviour instead of opinion: the churn rate shows who actually left.

Where the movement actually comes from: the middle group

• Always ask at the same point: immediately after purchase, after 30 days of use, or after a support contact — each produces a completely different number. Only a fixed measurement point makes periods comparable.
• Work on the passives: they are usually the largest group and sit one or two points below the promoter threshold. Two points from ten of them moves the score further than any rescue attempt on committed critics.
• Add an open follow-up: «why that rating?» costs nothing and delivers the cause the number itself never shows. Without it you know something is wrong but not what.
• Read it as a trend, not a snapshot: individual cohorts swing hard, especially on small samples. Three or four measurements make a line you can actually decide on.

Background and sources

• Bain & Company / Net Promoter System — «Measuring Your Net Promoter Score» — formula and group definitions from the originator of the metric.
• Qualtrics — «Net Promoter Score (NPS): The Ultimate Guide» — basis for the industry-agnostic band scale above.
• Wikipedia — «Net promoter score» — origin of the metric and the academic criticism of its growth claim.