NPS calculator

By the Gather team · Published August 18, 2026 · Last updated August 18, 2026 · Free, no signup, nothing stored

Enter your promoter, passive, and detractor counts to get your Net Promoter Score, the percentage breakdown, and the margin of error on the score itself, which almost nobody reports and which decides whether your quarter-over-quarter change is real.

How NPS is calculated

NPS = %promoters - %detractors

Promoters  = scored 9 or 10
Passives   = scored 7 or 8 (counted in the base, not in the score)
Detractors = scored 0 through 6

The score runs from -100 to +100. Passives dilute your score by sitting in the denominator without contributing to the numerator.

The margin of error nobody reports

NPS is a difference of two proportions, so it carries more sampling error than a single percentage. With 200 responses your 95 percent margin is roughly plus or minus 10 points. That means an NPS that moved from 32 to 38 has probably not moved at all.

This calculator shows that margin. Report it alongside the score, especially to a board, or you will end up defending noise as a trend.

What NPS does not tell you

NPS is a thermometer. It tells you there is a fever, never what caused it. The number moved and nobody in the room can say why is the single most common complaint I hear about it.

Two fixes:

• Always pair it with an open ended follow-up, and actually read the responses. The verbatim is the finding, the score is the headline.
• Probe the answer they just gave. A follow-up written from what they actually said gets you the reason. That is exactly what AI-moderated interviews do at scale, and why our brand health tracker reports attribute drivers next to the score.

Benchmarks, with a caveat

Cross-industry NPS benchmarks are close to useless because the response scale is interpreted differently by culture, industry, and channel. A 30 in enterprise software and a 30 in airlines are not comparable. Track your own score over time against a consistent instrument instead, which is what a proper tracker is for.

Frequently asked questions

How do you calculate NPS?

Subtract the percentage of detractors, who score 0 to 6, from the percentage of promoters, who score 9 to 10. Passives who score 7 or 8 count in the base but not in the score. The result runs from -100 to +100.

What is a good NPS score?

There is no universal answer, and cross-industry benchmarks are misleading because scale interpretation varies by industry and culture. Track your own score over time with a consistent instrument instead of chasing a benchmark.

Why do passives count?

They sit in the denominator when you calculate percentages, so a large passive group pulls your score toward zero without helping it. That is by design: passives are not actively recommending you.

How many responses do I need for NPS?

At least 200 for a stable read. Below that the margin of error on the score exceeds 10 points, which means normal quarter-over-quarter variation will look like a trend.

Is a change in NPS meaningful?

Only if it exceeds the margin of error, which this calculator shows. With 200 responses, a move of fewer than about 10 points is probably noise.

Is this NPS calculator free?

Yes. No signup, nothing stored, calculation runs in your browser.