Almost everything covered in the rest of this category's articles measures behaviour: clicks, visits, conversions, revenue. NPS (Net Promoter Score) measures something different and complementary, not what people do, but what they think and feel about the business, summed up in a single question that, used well, fairly reliably predicts the business's future growth: "on a scale of 0 to 10, how likely are you to recommend this business to a friend or colleague?"
Why that specific question and not another
There are many ways to ask about customer satisfaction ("how was your experience?", "are you happy with the service?"), but most are vulnerable to politeness bias: people tend to answer positively even when not entirely satisfied, simply to avoid seeming difficult or out of laziness to explain the problem. The NPS question works better because it asks for something with real consequences for the respondent (putting their own reputation on the line by recommending something to someone they know), which pushes toward a more honest answer than a simple satisfaction rating.
How NPS is calculated
Answers from 0 to 10 are grouped into three categories: detractors (0 to 6, unhappy people who may even speak badly of the business), passives (7 and 8, satisfied but unenthusiastic, vulnerable to leaving for a competitor if a better offer comes along) and promoters (9 and 10, enthusiastic customers who are probably already recommending the business spontaneously). NPS is calculated by subtracting the percentage of detractors from the percentage of promoters, ignoring passives in the final calculation. The result ranges from -100 (all detractors) to +100 (all promoters).
What counts as a good NPS
There is no universal threshold valid across every industry, because average NPS varies a lot by sector (industries with more structural friction, like telecoms or insurance, tend to have lower average NPS than industries with more direct, personal dealings). As a general guide, an NPS above 0 is considered acceptable, above 30 is considered good, and above 50 is considered excellent, but the more useful comparison is still against the business's own history, not a generic industry benchmark.
The follow-up open question: where the real value lies
The NPS number alone tells you whether things are going well or badly, but not why. The part that multiplies this metric's real value is always including an immediate open follow-up question ("what was the main thing that influenced your score?"), which gives the qualitative context needed to know what to improve. Without that open question, NPS is just a thermometer; with it, it becomes a direct source of improvement ideas, free and with no need for any additional market research.
When and how to ask
Timing matters: asking too soon (right after the first interaction) does not give enough time to form a solid opinion of the business, and asking too late can blur the memory of the real reason behind the score. It is common to send it shortly after a significant purchase or service is completed, and periodically (every six or twelve months) for ongoing-relationship customers, rather than just once at the start of the relationship.
What to do with detractors: the step almost nobody completes
The most common mistake with NPS is collecting the number and doing nothing with it. The real value shows up when you reach out directly (personally, not through automation) to detractors to understand their problem and, where possible, fix it, because a detractor whose problem gets genuinely resolved can become one of the most loyal customers, while an ignored detractor keeps speaking badly of the business indefinitely without anyone knowing.
How to leverage promoters beyond the score
Promoters are not just a good data point, they are an active opportunity: it is the natural moment to ask them for a public review (on Google, on the relevant industry platform) or to invite them into a referral programme, precisely because they have already expressed in writing their willingness to recommend the business. Letting that moment pass without asking for anything wastes the enthusiasm exactly when it is at its peak.
An example of how a detractor became the most loyal customer
A moving company received a score of 3 out of 10 from a customer who, in the open question, explained the crew had arrived two hours late with no warning. Instead of filing that response away with the rest, the manager personally called the customer the next day, apologised specifically (not generically), explained what had gone wrong in the scheduling, and offered a discount on a future service as compensation. That same customer, a year and a half later, had referred the company to two relatives and had hired it again for a second move. The cost of that call was barely fifteen minutes; the value of the recovered customer, far higher than any acquisition campaign would have cost to land an equivalent new customer.
Why NPS works better as a conversation than as a report
Reducing NPS to a number that shows up once a month in a report, with no active follow-up on individual responses, wastes most of its real value. The metric works best when built into the business's day-to-day: someone reviews the responses every week, not just the aggregate number, and acts on individual cases while the reason behind the score is still fresh, both for the customer and for whoever can fix it.
Segmenting NPS by customer type or service
Looking at a single overall NPS can hide important differences between different segments of the business: one specific service might have an excellent score while another has been dragging a mediocre one for months, something the aggregate figure completely masks. As with any other metric, breaking NPS down by service, customer type or relationship tenure usually reveals where the real problem (or the real strength) that deserves reinforcing actually lies.
Step by step: launching your business's first NPS survey
First, choose the send timing: ideally, three to seven days after the purchase or service is completed, when the experience is still fresh but there has already been time to form a complete opinion. Second, write the main question exactly using the 0-to-10 scale and the standard phrasing ("how likely are you to recommend...?"), avoiding variations that make it harder to compare results against the industry standard. Third, always add the open follow-up question immediately after, without which the score loses most of its practical usefulness. Fourth, choose the sending tool based on what you already use (a simple form linked from an email, a dedicated NPS tool, or a feature built into the CRM) without overcomplicating the implementation more than necessary to get started. Fifth, set up a clear process for who reviews responses each week and who is responsible for contacting detractors, because without that step NPS stays a nice-looking number with no real impact. Sixth, after two or three months of accumulated responses, calculate the overall NPS and compare it month to month, starting to build the own track record that will give meaning to every future figure.
Frequently asked questions
How often should I send the NPS survey to my customers?
For customers with a one-off relationship (a single purchase), it makes sense to send it shortly after that purchase. For customers with an ongoing relationship (subscriptions, recurring services), once or twice a year is usually enough, avoiding survey fatigue from sending it too frequently.
Is NPS useful for very small businesses with few customers?
With very few responses, the NPS calculation can be unstable (a single response can move the score several points), so it is worth interpreting it cautiously and giving more weight to the qualitative open-question answers than to the exact number until a larger base of responses has been gathered.
Should I send the NPS survey by email, SMS or some other way?
Whichever channel works best depends on where the business has the most regular contact with its customers; the important thing is that it be a channel where the person already expects to receive communication from the business, so as not to trigger rejection from being perceived as spam.
What do I do if my NPS is negative?
A negative NPS (more detractors than promoters) is a serious signal deserving immediate attention, starting with a detailed review of detractors' open-ended answers to identify the main problem, rather than trying to improve the number in the abstract without understanding the cause.
Does NPS really predict the business's future growth?
There is reasonable evidence of correlation between a high NPS and better long-term growth (promoters tend to buy more, stay longer and bring in new customers through referrals), though it is not an absolute guarantee nor a replacement for other business metrics, it is a complementary indicator, not the only one worth watching.
Can I combine NPS with other satisfaction metrics, like CSAT?
Yes, and it is usually recommended: CSAT (satisfaction with a specific interaction, like a customer service call) is more useful for measuring specific moments, while NPS measures the overall relationship with the business, so they complement each other well rather than replacing one another.