Net Promoter Score (NPS) is a customer loyalty metric built around one question: how likely are you to recommend this company to a friend or colleague? That question, scored on a 0-to-10 scale, produces a number between -100 and +100 that tells you whether your customers are working for you or quietly against you.

Fred Reichheld developed the metric with Bain & Company, and it went public in a 2003 Harvard Business Review article. It has since become one of the most widely used customer experience measures, mostly because it's simple enough to get real organisational buy-in and because the score tracks closely with behaviours that affect revenue: referrals, repeat purchase, and reduced churn.

How it works

The survey prompt is standardised: "On a scale of 0 to 10, how likely is it that you would recommend [Company/Product/Service] to a friend or colleague?"

Respondents fall into three groups. Promoters (9-10) are loyal, likely to recommend you, and likely to come back. Passives (7-8) are satisfied but not particularly enthusiastic. They won't damage your reputation, but they won't build it either, and they're not hard to lose to a competitor. Detractors (0-6) are unhappy. They're at higher risk of leaving and some will actively put people off.

The calculation

NPS = percentage of Promoters minus percentage of Detractors.

Passives count toward the total response pool, which affects the percentages, but drop out of the formula entirely. If 60 out of 100 respondents are Promoters and 20 are Detractors, your NPS is 40.

What a good score looks like

Any positive score means Promoters outnumber Detractors. Bain's guidance puts anything above 20 as favourable, above 50 as excellent, and above 80 as world-class. The grocery sector tends to average around 30; consumer payments can run into negative territory. Industry benchmarks tell you more than an absolute target number.

Relational vs transactional NPS

NPS programs generally run in one of two modes. Relational NPS goes out on a regular cadence, quarterly or annually, to measure the overall relationship. Transactional NPS fires after a specific interaction: a support call, a delivery, a renewal.

Relational is better suited to tracking loyalty trends over time. Transactional helps you understand where individual touchpoints are working or breaking. Many practitioners caution against the transactional version, though. "Would you recommend us?" is a question about the brand, not about a single call to the helpdesk.

What NPS doesn't tell you

A score on its own is nearly useless as a diagnostic. It tells you the ratio of happy to unhappy customers. It doesn't tell you why.

To get anything actionable, you need to pair the rating question with an open-ended follow-up: "What's the main reason for your score?" The verbatim responses are where the insight actually sits.

NPS is also worth reading alongside other metrics. Customer Effort Score (CES) measures how hard it was to complete a task, which predicts loyalty in its own right. Customer Satisfaction Score (CSAT) captures how someone felt about a specific interaction. Together they give you a more complete picture than any single number provides.

One more practical note: over-surveying kills response rates. If every interaction triggers an NPS request, customers tune them out.

Why it's worth tracking

Despite its limitations, NPS is a useful headline metric. It's easy to explain, easy to track over time, and it connects to revenue-relevant behaviour. A business with strong NPS has customers who stay and bring others. A business running negative has a more urgent problem.

The number is a starting point, not an answer.