Net Promoter Score calculator
Calculate NPS and its margin of error from response counts or raw 0–10 scores.
A clear answer. Here’s how.
NPS = percentage of promoters (9–10) minus percentage of detractors (0–6); passives (7–8) count only in the total. With shares p and d the standard error is √((p + d − (p − d)²) ÷ n) × 100 points, and the interval is NPS ± z × standard error, clipped to −100 to 100. This is a normal approximation, so very small samples give rough intervals. Compare surveys only when the question wording and timing are the same.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Enter
- Promoter, passive and detractor counts
- Promoters (scores 9–10)
- 60
- Passives (scores 7–8)
- 30
- Detractors (scores 0–6)
- 10
- Confidence level
- 95%
Example result
- Net Promoter Score
- 50
- Responses
- 100
- Promoters (9–10)
- 60 (60.0%)
- Passives (7–8)
- 30 (30.0%)
- Detractors (0–6)
- 10 (10.0%)
- Standard error (points)
- 6.7082
- 95% confidence interval
- 36.9 to 63.1
- Margin of error (points)
- ±13.1
NPS = % promoters − % detractors, from −100 to 100. The standard error is √((p + d − (p − d)²) ÷ n) × 100 for promoter share p and detractor share d, which is a normal approximation; very small samples or extreme shares make the interval rough. Passives count in n but not in the score.