Net Promoter Score Calculator

How it is calculated

You enter how many respondents fall into each group, and the tool turns the counts into shares of the total: total = promoters + passives + detractors, then NPS = (promoters − detractors) / total × 100, rounded to a whole number. Passives (scores 7 to 8) never appear in the numerator, but they are in the total, so they pull both shares down. The result runs from −100 (all detractors) to +100 (all promoters). A rating is added from fixed bands, judged on the rounded score you see: above 50 is Excellent, 0 to 50 is Good, and below 0 is Needs improvement. It also shows the promoter share as a percentage of all answers. The counts must be whole numbers (they are people), none can be negative, and the total must be above zero; otherwise no result is shown.

Common mistakes

• Entering the 0-10 scores or their average instead of counts of people in each group. The tool needs the number of promoters (9-10), passives (7-8) and detractors (0-6).
• Leaving the passives out. They do not change the top of the formula, but they enlarge the total, so omitting them overstates both promoter and detractor shares.
• Entering a share such as 60 for "60%" in all three boxes without a matching total, or a fractional count like 60.5, which gives no result. Use whole numbers of respondents.
• Comparing scores from very small samples. With 10 responses, one person moving groups changes the NPS by 10 points.
• Reading a score of exactly 0 as good news or as bad news. It means promoters and detractors are equal in number; the tool rates 0 as Good (0 to 50), and only scores below 0 get Needs improvement.