BYTETOOLS

NPS Calculator

Calculate your Net Promoter Score from group totals or a full 0–10 response distribution, with a margin of error, likely range and a distribution chart.

28
Net Promoter Score
46.7%
Promoters
34.4%
Passives
18.9%
Detractors
900
Responses
±5.0
Margin of error (95%)
23 to 33
Likely range
—
Average rating

Positive but modest — you have more promoters than detractors, with plenty of indifferent passives in between.

NPS = % promoters − % detractors  ·  margin of error = z × √(σ² ÷ n) × 100, where σ² = p_promoter + p_detractor − (p_promoter − p_detractor)²

Worked example: 500 promoters, 300 passives and 200 detractors out of 1,000 responses gives 50% − 20% = an NPS of 30. The variance of the ±1 scores is 0.5 + 0.2 − 0.3² = 0.61, so the 95% margin of error is 1.96 × √(0.61 ÷ 1,000) × 100 = ±4.8 points — the true score is somewhere around 25 to 35.

NPS deliberately throws away the passives, which is why a score can stay flat while a lot changes underneath it — always look at the full distribution as well as the headline number. The margin of error assumes your respondents are a random sample of your customers; in practice survey responses skew towards people with strong opinions, so the real uncertainty is usually wider than the arithmetic suggests. Comparing your score with a published industry benchmark is only fair if the survey wording, channel and timing match. Every calculation happens in your browser and no responses are uploaded.

What is the NPS Calculator?

Net Promoter Score is the percentage of promoters who scored 9 or 10 minus the percentage of detractors who scored 0 to 6, with the passives in between deliberately ignored.

  • Two input modes — group totals or the full eleven-point distribution
  • Margin of error and likely score range at 80%, 90%, 95% or 99% confidence
  • Colour-coded response distribution chart in scale mode
  • Average 0–10 rating alongside the NPS itself
  • Plain-English interpretation of what your score band means
  • Entirely client-side — survey responses never leave your browser

How to use the NPS Calculator

  1. 1

    Choose whether to enter group totals or the full 0–10 response distribution.

  2. 2

    Pick a confidence level for the margin of error — 95% is standard.

  3. 3

    Enter your promoter, passive and detractor counts, or the count for each score from 0 to 10.

  4. 4

    Read the score, the group percentages and the likely range in the stat rows.

  5. 5

    In distribution mode, check the bar chart to see where responses actually cluster.

About the NPS Calculator

Net Promoter Score is the percentage of promoters who scored 9 or 10 minus the percentage of detractors who scored 0 to 6, with the passives in between deliberately ignored. This calculator accepts either bulk promoter, passive and detractor totals or the full eleven-point response distribution, and works out the score, the group percentages and the average rating.

It also does something most NPS calculators skip: it puts a margin of error on the result. A score of 30 from 200 responses is a very different claim from a score of 30 from 5,000, and the tool shows the likely range at your chosen confidence level so you know whether a change since last quarter is real movement or survey noise.

Enter the full 0–10 distribution and you also get a colour-coded bar chart showing exactly where responses cluster, which often says more than the headline number does. All of it is computed in your browser: no survey responses are uploaded, nothing is stored between visits, and the page works perfectly well with no connection.

Frequently asked questions

How is Net Promoter Score calculated?

Take the percentage of respondents who scored 9 or 10, subtract the percentage who scored 0 to 6, and drop the percentage sign. Passives who scored 7 or 8 count towards the total responses but are excluded from both sides, so the result runs from −100 to +100.

What is a good NPS score?

Anything above zero means promoters outnumber detractors. Above 30 is generally considered good, above 50 excellent, and above 70 world-class. Benchmarks vary enormously by industry, so comparing against your own trend is far more useful than against a published average collected with different survey wording.

How many responses do I need for a reliable NPS?

Enough that the margin of error is smaller than the change you are trying to detect. As a rough guide, a typical response mix needs several hundred responses to get the 95% margin of error under five points. This calculator shows the margin directly so you can judge it for yourself.

How is the NPS margin of error calculated?

Each response is treated as +1 for a promoter, 0 for a passive and −1 for a detractor. The variance of those values is the promoter share plus the detractor share minus the square of their difference; the margin of error is the critical z value times the square root of that variance divided by the sample size, scaled to points.

Why does NPS ignore passives?

By design — the score is meant to contrast enthusiasm against dissatisfaction, and passives sit in the middle by definition. The side effect is that a headline score can stay completely flat while passives shift into promoters and detractors underneath it, which is why the distribution chart matters as much as the number.

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