Formula, in SaaS Metrics

NPS Formula

The Net Promoter Score (NPS) formula calculates customer loyalty by subtracting the percentage of detractors from the percentage of promoters, providing a key indicator of growth potential.

3 variables. Published Mar 12, 2026. Updated Mar 27, 2026. By AI Biz Hub.

Formula

NPS = Promoters Percent - Detractors Percent

Variables

NPS

The Net Promoter Score, ranging from minus 100 to plus 100. It is a net count of advocates over critics, not an average rating; anything above 0 means more promoters than detractors.

Promoters Percent

The percentage of respondents scoring 9 or 10 (promoters). Loyal customers likely to refer others.

Detractors Percent

The percentage of respondents scoring 0 to 6 (detractors). Unhappy customers who may churn or warn others. Passives (7 to 8) are excluded from both sides.

Step by step

1

Set the baseline case with the real calculator inputs.

Promoters = 120, Passives = 45, Detractors = 35, Industry = SaaS
2

Bucket every response into promoters (9 to 10), passives (7 to 8), and detractors (0 to 6), then convert promoter and detractor counts to percentages of all respondents.

Of 200 responses, 120 promoters and 35 detractors are 60% and 17.5%.
3

Apply the formula and read the first calculator outputs, not just the headline assumption.

The calculator lands with total responses at 200 and nps score at 42.5.
4

Re-run on a meaningful sample size, since a handful of responses can swing NPS wildly and make a flattering score unreliable.

With only 20 responses, two extra detractors move the score by 10 points.

Worked example

Nps sample case

Promoters

120

Passives

Detractors

Industry

SaaS

NPS = Promoters Percent - Detractors Percent using promoters 120, passives 45, detractors 35, industry SaaS.

The calculator lands with total responses at 200 and nps score at 42.5.

Common variations

Percentage inputs usually need a gross-versus-net check so the same base is being compared.

Scenario variants are useful because fixed assumptions rarely survive contact with real life unchanged.

Use Net Promoter Score Calculator to compare the baseline result with one stressed case before relying on a single answer.

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Sources

The Ultimate Question 2.0: How Net Promoter Companies Thrive in a Customer-Driven World , Harvard Business Review Press
What is a good Net Promoter Score? Benchmarks, best practices, and more , Bain & Company

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