How to Calculate Net Promoter Score


On the surface, calculating your NPS is simple. You need two numbers: Subtract the percentage of detractors your business has from the percentage of promoters your business has. So if you have 100% promoters, you have a NPS of 100 (100-0). If you have 60% detractors and 40% promoters, you have an NPS of -20 (40-60).

But telling you that isn’t particularly helpful. What’s a promoter? What’s a detractor? When should you calculate your NPS? What should you do with it when you’ve calculated it?

When you’ve finished this guide you’ll have the answer to all these questions and more.

What are Promoters and Detractors?

When Fred Reichheld was working on the original research which defined the Net Promoter Score, he noticed customers clustered into three groups, and that these groups could be neatly mapped onto a 0-10 scale.

  • Promoters (Score of 9 or 10) – high repurchase rates, and very likely to refer new customers (80% of all referrals).
  • Passives (Score of 7 or 8) – repurchase and referral rates up to 50% lower than promoters. Motivated mainly by inertia, not enthusiasm for your business.
  • Detractors (Score of 0-6) – account for up to 80% of negative word-of-mouth. Just because they’re paying you money doesn’t mean they’re good for your company, once you consider their effect in lost sales and support costs.

The Net Promoter Formula

NPS is usually calculated using the results of the question,

On a scale of 0-10, to what extent would you recommend company x to a friend or colleague?

This question wasn’t plucked out of thin air – a lot of research went into finding out which question had the best predictive power for a company’s future growth.

But if the standard question isn’t right for your circumstances, don’t get hung up on it – what’s important is that you have a question that everyone in your team understands, and you have a straightforward way of grouping the scores from that question into promoters, detractors and passives.

It’s this simplicity that’s important. Net Promoter is about getting everyone working towards the same goal – measuring customer loyalty – so it’s important that everyone understands the scoring system.

NPS Calculator

To get a feel for how different numbers of detractors, passives and promoters affect your score, try entering different score counts:

For example, if 20 people have scored you ‘9’, type ‘20’ in the box marked ‘9’






When should I calculate my NPS?

This depends on your circumstances. There’s no one-size-fits-all answer, but if you’d appreciate some advice, we love to chat about customer satisfaction and we don’t do awkward, pushy sales, so give us a call? But in general…

The NPS system describes two main types of survey: transactional (every time a customer completes a touchpoint with you) and relationship (surveying a cohort of your customers at a moment in time).

Done well, transactional surveys can replace a lot of the need for relationship surveys. If you’re surveying most of your customers naturally as they interact with you, then a ‘quarterly customer survey’ or ‘monthly customer attitude poll’ isn’t going to tell you a lot you don’t already know.

Transactional surveys give you constant visibility of your live NPS score. Which is nice. But, like any business metric, it’s not helpful to obsess over it day-to-day. So when should you look at it?

NPS score month by month

You need to make two choices when you calculate your NPS score from transactional surveys:

  • How often are you going to calculate it? As a rough guideline, we’d recommend you do this monthly. Less often, and you run the risk of ‘coasting’ in between updates, but any more often and you run the risk of being thrown off-course by day-to-day swings in your data.
  • What time period are you calculating for? If you’re calculating your score every month, are you just looking at the previous month’s data, or a rolling time window (i.e. past 3, 6 or 12 months)?

    If you’re calculating over a 12-month window, good scores from the past may pull up your average and mask bad scores you’re getting today. But, calculating month-to-month can give you very volatile data that it’s hard to make sensible business decisions with. As a broad guideline, we’d suggest a 3-month rolling window… But ultimately, the right answer depends on your circumstances.

But always, always remember: It’s great to know your NPS score, but it’s the NPS system that improves customer satisfaction. However you choose to measure things, your primary focus should always be finding and fixing individual customer issues in real time.

What data should I use to calculate my NPS?

We’ve covered which time period you should calculate NPS over, but there’s another important question: how should you ‘slice’ your team or organisation’s data?

Again, there’s no ‘one true answer’ here – get in touch if you’d like to discuss your circumstances. However, let’s look at some of the factors which shape the answer:

Should I calculate NPS for Individual Advisors?

There are arguments for and against this. Most strongly against is the fact that the traditional NPS question asks would you recommend the organisation?, so it’s unfair to pin the answer to that question to any one person.

In practice though, we disagree. We’ve helped hundreds of organisations put customer feedback systems in place, and we’ve seen calculating satisfaction scores for individuals lead to brilliant results.

NPS scores by staff member

This isn’t an unqualified recommendation, though. There’s a few things you need to be aware of:

Organisation vs Individual

People who point out that the NPS question is about the organisation have a point. Be very, very careful about assuming that bad scores mean bad performance, especially when you’re working with a limited amount of data.

We strongly recommend that you ask a few short, customer-centric follow up questions on your NPS surveys, and this is one of the reasons why.

Asking targeted questions like “How helpful was your advisor today?” alongside general sentiment questions like NPS allows customers to be specific about their feelings. As a customer yourself, have you ever wanted to simultaneously criticise an organisation but praise an individual within that organisation who tried to help you?

You should also never be asking the NPS question without a question for free-text feedback, and this feedback will normally make clear whether the score relates to the individual or the organisation or a whole.


Obviously, culture is massively important here. Depending on your organisation, it may not be appropriate to share individual NPS scores, even within a team. If you do choose to share scores, make sure that everyone understands the context around them. An individual with low NPS might be your star performer, because they’re troubleshooting customers with difficult problems.

Comparing Individuals

Following on from the previous two points, be very careful about benchmarking NPS for individuals. As a rule, we’d say that benchmarking satisfaction is a waste of time, and this is doubly-true when attributing scores to individual advisors. It’s a useful tool to identify team members who might need extra coaching, not an arbitrary benchmark to hold your team to.

Skewed Data

And finally, on that note – have you ever had a comment card pressed into your hand and been asked,

Please give me a 9 or a 10… my bonus depends on it!

As a customer, did you feel able to give truthful, helpful feedback in that situation? Or do you just give a 10 and move on with your life?

Never use NPS as a basis for any form of individual incentivisation. People will always try to ‘game’ the system. The best scores will go to your team members who are best at sweet-talking customers, you’ll miss out on a huge amount of constructive feedback, and lose a reliable measure of how satisfied your customers really are.

Can I calculate NPS for other areas of my company?

If it’s a meaningful way of dividing up your business, it can be a useful way of segmenting your NPS. Depending on your circumstances, it can be helpful to compare things like contact centre teams, sites or product lines. But in most cases, the issues we discussed around comparing advisors will still apply.

Remember to put things in context, build a positive culture around satisfaction scores, and definitely don’t rely on benchmarks.

Where next?

Introduction to NPS

What’s Net Promoter? It’s not a question, and it’s not just a score. But get it right and it can transform how your team relate to your customers.

« Read more

NPS Surveys

Your survey is fundamental to getting NPS right - learn with examples and templates the best practices for an NPS survey.

Read more »

Have we answered your questions?

Helping people use feedback better is what gets us out of bed on a morning. No matter if you’re new to this or a feedback guru, you can call us – we’d love to hear from you.