NPS Calculator
Net Promoter Score from your response counts — with the margin of error, which is usually left out.
NPS asks how likely someone is to recommend you, from 0 to 10.
How the nps calculator works
NPS asks how likely someone is to recommend you, from 0 to 10. Scores of 9 and 10 are promoters, 7 and 8 are passives, and everything from 0 to 6 is a detractor. The score is the percentage of promoters minus the percentage of detractors, so it runs from −100 to +100.
The design throws away information deliberately: passives count for nothing, and a 0 counts the same as a 6. That makes it blunt, and it is the main criticism of the measure.
The thing almost nobody reports is the margin of error. NPS is a difference of two proportions, so its confidence interval is wider than an ordinary percentage. With 100 responses it is roughly ±10 points, which means a move from 32 to 38 is very likely noise.
Formula: NPS = %promoters − %detractors
Worked examples
| Inputs | Net Promoter Score | Note |
|---|---|---|
| 420 promoters, 260 passives, 120 detractors | 37.5 | NPS 37.5 |
| A small sample | 37.5 | same score, much wider error |
| More detractors than promoters | -33.3 | negative NPS |
FAQFrequently asked questions
How is NPS calculated?
Percentage of promoters (9–10) minus percentage of detractors (0–6). Passives (7–8) count in the denominator only.
What is a good NPS?
Above 0 means more promoters than detractors; above 50 is excellent and above 70 is rare. It varies enormously by industry.
Why does the margin of error matter?
Because NPS is a difference of two proportions, its interval is wide. On 100 responses it is about ±10 points, so small movements are noise.
Why do passives count for nothing?
By design — the measure deliberately ignores the middle. That bluntness is the main criticism of it.
Can NPS be negative?
Yes, down to −100 if every respondent is a detractor.
Where these figures come from
- Reichheld (2003), Harvard Business Review — The One Number You Need to Grow — the paper that introduced Net Promoter Score
- Financial Reporting Council — the UK accounting regulator
Last checked: September 2026. These are the industry-standard definitions; where companies commonly disagree, the page says so.