Net Promoter Score Calculator

This calculator computes Net Promoter Score as Promoter % minus Detractor % (line 55), after first converting each raw count to a share of Total Responses (lines 52-54). Promoters moves the score the most — nudging Promoters up or down by 10% moves NPS about twice as much as the same-sized nudge to Passives or Detractors at the defaults, because Promoters both raises the positive term (Promoter %) directly and, by adding to Total Responses, slightly dilutes every other share too. Detractors lowers NPS directly, since it subtracts from the score through Detractor %.

Passives also lowers NPS, which is easy to miss since Passives never appears in the NPS formula itself (line 55 only references Promoter % and Detractor %) — but adding Passives responses grows Total Responses, the shared denominator, which shrinks the gap between Promoter % and Detractor % as a share of the whole. Classification (lines 57-61) applies four fixed thresholds to the resulting score: 71 or above is "Excellent," 31 to 70 is "Great," 0 to 30 is "Good," and anything negative is "Needs Improvement" — at the default counts, an NPS of 50 lands in the "Great" tier, not "Excellent." The 9-10/7-8/0-6 promoter/passive/detractor split and the underlying single-question methodology both trace back to Fred Reichheld's 2003 Harvard Business Review article "The One Number You Need to Grow," which introduced the "how likely are you to recommend" question as a loyalty metric after finding it outperformed satisfaction ratings and repurchase-intent questions at predicting actual customer behavior. This calculator does not weight responses by respondent representativeness, does not compute a confidence interval around the score, and returns an all-zero result rather than dividing by zero when Promoters, Passives, and Detractors are all 0 (line 9).