How To Calculate Net Promoter Score

The Net Promoter Score is a customer loyalty metric built from a single survey question: how likely are you to recommend this company to a friend or colleague, on a scale of zero to ten.

Responses are sorted into three groups. Scores of nine or ten are promoters, seven or eight are passives, and zero to six are detractors. The grouping is fixed, so the same response always lands in the same group.

The score is the percentage of promoters minus the percentage of detractors. Passives are included in the total when working out the percentages but do not otherwise affect the score, which is why a large passive group dilutes the number toward zero.

The range runs from minus one hundred, when every respondent is a detractor, to plus one hundred, when every respondent is a promoter. A score of zero means promoters and detractors are equally balanced.

Because the score is a difference of percentages rather than a simple average, it can fall even when satisfaction rises. If promoters and detractors both grow, the net figure can move in either direction, so the underlying percentages matter as much as the headline.

The metric is popular because it is simple to collect and easy to compare over time. A single question keeps response rates high, and one number is easy to track quarter by quarter.

Benchmarks vary widely by industry. A score that is strong in one sector may be ordinary in another, so the number is most useful when compared against your own history or against direct competitors.

The score is a directional indicator, not a diagnosis. It tells you whether loyalty is improving or slipping, but the reasons come from the verbatim comments and the follow-up questions rather than from the number itself.

Detractors are often more informative than promoters. A detractor who can be reached and resolved can become a promoter, so the score is most valuable when it drives follow-up rather than just reporting.

Sample size matters. A score from twenty responses is noisy and can swing sharply with a single reply, while a score from several hundred is far more stable. Treat small-sample scores with caution.

The method of collection affects the result. An in-app prompt reaches a different group from an email survey, and a survey sent only to active customers will flatter the score. Keep the method consistent to make comparisons fair.

The score can be calculated for a whole business or for a specific journey, such as onboarding or support. Journey-level scores are usually more actionable because they point to a particular part of the experience.

It sits alongside other measures rather than replacing them. Retention, repeat purchase and revenue per customer tell you what actually happened, while the score tells you what customers say they intend.

The calculator models the three response counts and nothing more. It does not know your sample, your industry benchmark or how the responses were collected, so treat the output as a summary of the data you entered.