Net Promoter Score: Why and how to measure it

Aleš Randa

6 min

NPS is essential in business. It strongly predicts growth potential, customer satisfaction and brand reputation. It is easy to measure, but easy to misinterpret. Companies also often don't know how to maximize the information.

Net Promoter Score is a basic indicator of customer satisfaction

NPS measures customer satisfaction with a product and their willingness to share it. All using a simple question, "On a scale of 1-10, how likely are you to recommend this product/company to your friends or colleagues?"

The final Net Promoter Score is one of the most important metrics for a company. It is closely related to:

  • With the potential of the company/product for sale and further growth.
  • With the state of public opinion, especially if you are interested in word of mouth and customer loyalty. Brands with quality customer care have up to 21 points higher NPS on average.
  • With client enthusiasm, that you can then target your marketing to

NPS is replacing difficult and expensive public opinion polls, mainly due to its simplicity and reliability. Invented by Frederick F. Reichheld and first introduced in the prestigious Harvard Business Press in 2002, the article was called "The One Number You Need to Grow" and is definitely worth reading.

How to calculate Net Promoter Score?

A scale of 1-10 indicates the likelihood that the customer will recommend the product/company to a friend or colleague. 1 indicates not likely, 10 very likely.

Depending on how many points each respondent answers, you can divide them into three types:

  • Promoters score 9 to 10 points. These are brand ambassadors. They love your brand, they talk about it everywhere they go, it's a solid part of their lifestyle. In other words, you have the greatest possible brand trust in the eyes of promoters.
  • Neutrals score 7 to 8 points. They do not actively promote the brand, whether they have a positive or negative experience. Don't include them in the NPS calculation, but they shouldn't fall into oblivion. Neutrals are very close to turning into promoters (just one or two points). This makes it worth thinking about how to win their hearts as well.
  • Critics are users scoring 6 and below. They are the most dangerous to the brand. They don't actively promote it, they have very low loyalty. In extreme cases, they may publicly criticize.

You calculate the total NPS score as the percentage of critics subtracted from the percentage of promoters:

NPS = % of promoters - % of critics

Let's illustrate everything with an example: was testing the new XYZ mop. 50 testers took part in the testing. 35 of them rated the probability of recommending the product to friends as very high (they answered 9 or 10). 8 testers chose the answer 7 and 8. We call these values neutral and do not include them in the calculation. Finally, 7 testers selected a score between 0 and 6.


  • Loyal testers: 70% (35 testers with a score of 9-10/50 testers in total)
  • Disloyal testers: 14% (7 testers with 0-6/50 testers in total)

NPS calculation:

NPS = loyal testers - disloyal testers

NPS = 56

How do you interpret NPS results?

The NPS ranges from -100 to +100. Negative numbers mean an excess of critics, positive numbers an excess of promoters.

Take anything from 0 as a positive result. It means more clients will recommend the brand than criticize it. Generally the top score is 70, but don't take this as an idol. For example, in 2018 Apple only had a score of 49, not even Google was great with 53. Always consider the industry average too. For example, in telecoms the average is 9, in car dealerships it's 43. And don't worry about a completely perfect score of 100 - no one in the history of business has ever gotten it.

For a negative result, consider a score less than 0. It means an excess of critics and a clear signal for activity. You need to start finding promoters, improving products or completely overhauling customer service. But again, consider the industry average. It can be negative ( for example -10) and if you then score for example -2, you are actually better off than your competitors.

How to get NPS in practice and how to get the most out of the survey?

The NPS questionnaire has only one question, the administration is very simple. However, to get the most information from the survey, it pays to make the design more comprehensive.

  • Present the survey while the customer is on your (conversion) page. Either right after opening or just before leaving. It is also common practice to pop up after the purchase is complete.
  • - Depending on your score, ask more questions. If a customer scores low (perhaps less than 6), ask why, and what you can do to improve. Let them know that you take their opinion seriously. 
  • If the review is positive, thank them but still ask what could be improved. Often you will get valuable suggestions.

We do the NPS calculation for you every time you test

In the calculation, we use both the average score with a scale of 1-10 and the average rating with a scale of 1-5.

  • The average score is based on the familiar question "How likely are you to recommend the product to your friends or colleagues?
  • The average rating, on the other hand, reflects the item "How satisfied are you with the product in general?

We clearly visualize the terms used in the reviews using word clouds.

This helps clients discover important product features. Word clouds are based on the frequency of individual words, within positive (+) and negative (-) statements in reviews.

It is often the case that word cloud "pluses" are the same words as word cloud "minuses". So, for example, the word "skin" is mentioned in both positive and negative contexts, which makes sense given the category. In this case, the text of the reviews themselves should also be perceived to make the context of each word cloud clearer.

If you get an exceptionally high NPS in testing, you will receive a special stamp

The stamp is a unique certificate for products that have been tested on a selected community, using our methodology, and received good results during testing.

It is given to products that have achieved a predetermined level of satisfaction from all testers during testing. In simpler terms, the stamp is only awarded to those products that have achieved an average of at least four stars out of a possible five in the satisfaction measure during testing.

The stamp always contains information that the product or service has been tested using the methodology. Recommendations are given by the selected community:

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