Net Promoter Score: Formula and Calculation

A net promoter score (NPS) calculator works out your score from the number of respondents in each recommendation group. Enter the counts of promoters, passives, and detractors to get an NPS from -100 to +100, along with the response total and group percentages.

Formula

NPS = percentage of promoters − percentage of detractors. Using response counts directly, the equivalent formula is NPS = 100 × (P − D) ÷ N, where P is the number of promoters, D is the number of detractors, and N is the total number of valid responses: promoters + passives + detractors. The result is expressed in NPS points, not as a percentage.

Respondents are grouped by their answer to the standard likelihood-to-recommend question, usually scored from 0 to 10:

• Promoters: scores of 9 or 10.
• Passives: scores of 7 or 8.
• Detractors: scores from 0 through 6.

The calculator’s inputs are counts in people; its percentages are shares of all valid responses. It subtracts the detractor share from the promoter share. Passives count in the denominator, but they are not added to or subtracted from the score.

Worked Example

With the calculator’s default values, there are 60 promoters, 30 passives, and 10 detractors. First find the total: N = 60 + 30 + 10 = 100 responses.

1. Promoter percentage = 100 × 60 ÷ 100 = 60%.
2. Detractor percentage = 100 × 10 ÷ 100 = 10%.
3. NPS = 60 − 10 = 50 points.

The same result comes from the count-based formula: 100 × (60 − 10) ÷ 100 = 50. The additional outputs are 100 total responses and 60.0% promoters and 10.0% detractors.

How to Calculate NPS from Survey Responses

For raw survey data, classify each valid answer before calculating. A spreadsheet is often enough for a basic survey: count scores of 9–10, 7–8, and 0–6, then apply the formula. Alternatively, calculate the promoter and detractor percentages separately using the same total number of valid answers, then subtract.

1. Choose the survey question and define which submitted answers are valid for this calculation.
2. Group each valid 0–10 answer as promoter, passive, or detractor.
3. Count the answers in each group and add them to get the response total.
4. Divide the promoter and detractor counts by that total, multiply each share by 100, and subtract detractors from promoters.

Do not round each group’s percentage too early. Calculate from the counts, or retain full precision through subtraction, and round the final score to a whole point when reporting. For example, 38 promoters, 42 passives, and 20 detractors produce 38% − 20% = 18 points.

How to Interpret the Score

NPS ranges from -100, if every valid respondent is a detractor, to +100, if every respondent is a promoter. A score of zero means the promoter and detractor percentages are equal; it does not mean that every respondent is neutral. Passives can be numerous and still leave the score at zero.

A positive score means promoters outnumber detractors in percentage terms. A negative score means detractors outnumber promoters. Neither outcome alone explains why people answered as they did. Read the score alongside response counts, comments, survey timing, and other customer measures.

NPS is not the percentage of people who would recommend a business. It is the difference between two percentages. A score of 50, for instance, does not mean that 50% of respondents are promoters; it means the promoter share exceeds the detractor share by 50 percentage points.

Comparing Scores and Common Mistakes

The formula is straightforward, but comparisons can mislead if the surveys are not comparable. Keep the question wording, response scale, audience, collection method, and timing consistent when tracking change. A score from one customer group or survey channel may not be directly comparable with a score from another.

• Leaving passives out of the denominator: Include all valid 0–10 responses, including scores of 7 and 8.
• Using the wrong cutoffs: Promoters are 9–10, passives 7–8, and detractors 0–6.
• Reporting a percentage instead of NPS points: The result is a point difference between two percentages.
• Mixing missing or invalid answers into the total: Exclude unanswered or out-of-range responses from both the counts and denominator; document the rule.
• Overinterpreting a small sample: A few responses can move the score substantially. Always show the response count and treat apparent changes cautiously.

There is no single NPS value that guarantees a particular level of customer loyalty or business performance. Benchmarks vary by industry, audience, survey design, and collection period. Use the score as one indicator and compare like with like rather than treating a generic benchmark as a universal target.

Frequently Asked Questions

Do passives count in the NPS formula?
Yes. Passives are included in the total number of valid responses, which is the denominator. Their scores do not directly increase or decrease the numerator, which is promoters minus detractors.

Can NPS be negative?
Yes. If the detractor percentage is greater than the promoter percentage, the result is negative. The lowest possible score is -100.

Is NPS a percentage or a score?
It is reported as NPS points. It is calculated by subtracting one percentage from another, but it is not the percentage of respondents who are promoters.

How do I calculate NPS in a spreadsheet?
Count valid scores of 9–10, 7–8, and 0–6. Then calculate 100 × (promoter count − detractor count) ÷ total valid responses. Make sure all three groups use the same response total.

Should I round NPS?
Calculate using unrounded counts or percentages, then round the final result for presentation. The standard score is commonly reported as a whole number of points.

Related

• Calculate Z Value: Formula, Examples, and Meaning
• X-Intercept Calculator: Find Where a Graph Crosses the x-Axis
• Calculate True Positive and False Positive Rates

in promoters | Promoters | people | 60 | 0
in passives | Passives | people | 30 | 0
in detractors | Detractors | people | 10 | 0
out nps | Net promoter score | points | 100 * (promoters - detractors) / (promoters + passives + detractors) | 0
out responses | Total responses | people | promoters + passives + detractors | 0
out promoter_pct | Promoters | % | 100 * promoters / (promoters + passives + detractors) | 1
out detractor_pct | Detractors | % | 100 * detractors / (promoters + passives + detractors) | 1