Net Promoter Score (NPS) Calculator

Compute your Net Promoter Score from survey responses, see confidence intervals, compare segments, and estimate how many responses you need.

NPS Customer Experience Business & Small Biz

Enter counts

Results

Net Promoter Score

+55

95% CI: +42 to +68

Total responses

130

% Promoters

61.5%

% Detractors

15.4%

Score quality

Excellent – you have far more Promoters than Detractors.

Distribution

DetractorsPassivesPromoters

How Net Promoter Score (NPS) is calculated

Net Promoter Score is a simple metric that summarizes how likely your customers are to recommend you. It is based on the classic question:

“On a scale from 0 to 10, how likely are you to recommend our company/product/service to a friend or colleague?”

Responses are grouped into three categories:

  • Promoters (score 9–10): loyal enthusiasts who are likely to recommend you.
  • Passives (score 7–8): satisfied but unenthusiastic customers.
  • Detractors (score 0–6): unhappy customers who may damage your brand through negative word of mouth.

NPS formula

Let:

  • \( P \) = number of Promoters
  • \( Pa \) = number of Passives
  • \( D \) = number of Detractors
  • \( N = P + Pa + D \) = total responses

Then:

\[ \text{NPS} = \left(\frac{P}{N} - \frac{D}{N}\right) \times 100 \]

This yields a score between −100 and +100.

Interpreting your NPS result

There is no universal “good” NPS, because expectations differ by industry, geography, and product type. However, many teams use these rough ranges:

  • < 0: more Detractors than Promoters – urgent issues to address.
  • 0 to 30: acceptable, but with clear room for improvement.
  • 30 to 50: strong customer loyalty.
  • 50 to 70: excellent – customers are highly likely to recommend you.
  • > 70: world-class – typically seen in beloved consumer brands.

Always compare your NPS against your own history and relevant industry benchmarks, not against generic global averages.

Why confidence intervals matter

NPS is based on a sample of your customers, not the entire population. That means there is sampling error. Two surveys with the same underlying customer sentiment can produce slightly different NPS values.

This calculator estimates an approximate confidence interval for your NPS using a binomial model for Promoters vs. Detractors. A 95% confidence interval of +42 to +68 means:

  • If you repeated the survey many times, 95% of the intervals would contain the true underlying NPS.
  • Differences smaller than this range may not be statistically meaningful.

Planning your NPS survey sample size

To plan how many responses you need, we approximate NPS as the difference between two proportions (Promoters and Detractors). For a conservative estimate, we assume maximum variance.

Sample size approximation

For a desired margin of error \( E \) (in NPS points) and confidence level with z-score \( z \):

\[ n \approx \frac{z^2 \cdot p(1-p)}{(E/100)^2} \] where \( p(1-p) \) is the variance term. For a conservative NPS estimate we use a relatively high variance (e.g. 0.25).

If you have a finite population \( N_{pop} \), we apply a finite population correction:

\[ n_{\text{adj}} = \frac{n}{1 + \frac{n-1}{N_{pop}}} \]

In practice, you should also consider:

  • Response rate – how many customers will actually answer.
  • Sub-segments – if you want reliable NPS by country or product, each segment needs enough responses.
  • Survey frequency – transactional NPS (after each interaction) vs. relationship NPS (periodic).

Best practices for using NPS

  • Always ask a follow-up “Why?” question. The score alone doesn’t tell you what to fix.
  • Close the loop with Detractors. Reach out, understand their issues, and try to resolve them.
  • Tag and categorize comments. Group feedback by theme (pricing, support, product quality, UX) to prioritize improvements.
  • Track NPS over time. Look at trends and correlate changes with product releases or policy changes.
  • Share results internally. NPS is most powerful when product, support, marketing, and leadership all see and act on the insights.

NPS Calculator FAQ

How do you calculate Net Promoter Score (NPS)?

NPS is the percentage of Promoters (scores 9–10) minus the percentage of Detractors (scores 0–6). Passives (7–8) are ignored. For example, if 60% of respondents are Promoters and 20% are Detractors, your NPS is 60 − 20 = +40.

What is a good NPS score?

Any score above 0 means you have more Promoters than Detractors. Many companies treat 30+ as good, 50+ as excellent, and 70+ as world-class. However, benchmarks vary widely by industry, so always compare against peers and your own historical scores.

How many responses do I need for a reliable NPS?

For a rough directional signal, 50–100 responses can be enough. For tighter precision (for example ±5 NPS points at 95% confidence), you often need a few hundred responses. Use the “Sample Size” tab in this calculator to estimate the number for your desired margin of error and confidence level.

Can I compare NPS between segments or over time?

Yes, but you should compare not only the raw NPS values, but also their confidence intervals. If the intervals overlap heavily, the difference may not be statistically meaningful. The “Compare Segments” tab in this tool calculates NPS and approximate confidence intervals for two segments so you can judge whether the gap is likely real.