NPS Surveys Explained: How to Calculate and Use Net Promoter Score

Net Promoter Score, usually shortened to NPS, is one of the most widely used customer loyalty measures. It is built on a single question, which makes it easy to run even for a very small business. But the score on its own tells you little. The value comes from asking at the right moments, reading the comments, and acting on what you learn.

This guide explains how NPS works, how to calculate it, how to run a survey, and where the metric falls short.

Net Promoter, Net Promoter System, Net Promoter Score and NPS are trademarks of Bain & Company, Inc., NICE Systems, Inc. (Satmetrix) and Fred Reichheld. The method was introduced by Fred Reichheld in the early 2000s.

The NPS question

An NPS survey asks customers one core question:

"On a scale from 0 to 10, how likely are you to recommend [business or product] to a friend or colleague?"

Answers are grouped into three categories:

Score	Group	What it suggests
9 to 10	Promoters	Enthusiastic customers who are likely to buy again and recommend you
7 to 8	Passives	Satisfied but not enthusiastic; could be tempted by a competitor
0 to 6	Detractors	Unhappy or indifferent customers who may leave or discourage others

Most surveys add an open follow-up question, such as "What is the main reason for your score?" That comment is often more useful than the number.

How to calculate NPS

NPS = % of promoters − % of detractors

Passives count toward the total number of responses but are not added or subtracted. The result is a number from −100 (everyone is a detractor) to +100 (everyone is a promoter). It is usually written as a whole number, not a percentage.

Worked example

Suppose 80 customers respond:

40 give a 9 or 10 (promoters): 40 ÷ 80 = 50%
24 give a 7 or 8 (passives): 30%
16 give 0 to 6 (detractors): 16 ÷ 80 = 20%

NPS = 50 − 20 = 30.

The official Net Promoter System site has a short explanation of measuring your Net Promoter Score.

What is a good NPS?

A positive score means you have more promoters than detractors, which is a reasonable first milestone. Beyond that, be cautious with benchmarks. Published "average NPS" figures vary widely by industry, country, survey method and who was asked, and many come from vendors using their own customer data. They are hard to compare with your own number.

The most useful comparisons are internal:

Your NPS this quarter versus previous quarters, measured the same way.
NPS for different customer groups: new versus long-standing, by product, by plan or by region.
The themes in detractor comments, and whether they shrink after you make changes.

Running an NPS survey

Relationship and transactional surveys

There are two common approaches:

Relationship NPS is sent on a regular schedule, for example once or twice a year, to measure overall loyalty.
Transactional NPS is sent after a specific event, such as finishing onboarding, a project delivery or a support case, to measure that experience.

A small business can start with one relationship survey a year and add a transactional survey at a key moment such as the end of onboarding.

Practical tips

Keep it short. The score question plus one open question is enough. Every extra question lowers the response rate.
Pick the timing carefully. Ask after customers have had enough experience to judge, not on day one.
Do not survey too often. Limit how frequently any one person is asked, so the survey does not become a nuisance.
Use the same wording every time so results stay comparable.
Record responses in your CRM against each contact so you can follow up and segment results.

Do not game the score. Asking customers to "please give us a 10", only surveying happy customers, or offering rewards for high scores produces a nicer number and useless data. If staff are rewarded for NPS, watch for these behaviors.

Close the loop

The most valuable step happens after the survey. "Closing the loop" means following up with respondents:

Detractors: contact them personally and quickly. Thank them, acknowledge the problem, and ask what would fix it. Some can be won back, and all of them teach you something. These customers are at high risk of churning; see reducing customer churn.
Passives: ask what would make the experience excellent. The answers often point to small, cheap improvements.
Promoters: thank them, and consider asking for a review, testimonial or referral, where your local rules and platform policies allow it.

Then group the comments into themes, such as price, speed, product quality or support, and fix the most common detractor issues first. Tell customers what you changed. It shows the survey was worth their time.

Limits of NPS

NPS is popular because it is simple, but it has well-known weaknesses:

Small samples swing wildly. With a few dozen responses, a handful of answers can move the score by many points. Look at trends over several periods.
It hides detail. The same score can come from very different mixes of promoters and detractors. Look at the distribution, not just the final number.
Intent is not behavior. Saying you would recommend a business is not the same as doing it. Compare NPS with actual repeat purchases, churn and referrals.
Response bias. The customers who answer may not represent all customers, and the very unhappy may already have left.
Cultural differences. People in different countries use rating scales differently, which complicates comparisons across regions.

Use NPS as one signal among several. Pair it with hard retention numbers such as churn and customer lifetime value, and above all with the comments customers take the time to write.