Net Promoter® Score definition and formula

Working in marketing often means dealing with math, and the formulas can be mind-bogglingly complicated.

At what point in the purchase funnel do you see the greatest amount of conversions? How many clicks on your blog come from organic sources? And at what time do those clicks seem to peak?

Performing all of those calculations can make your head spin. The Net Promoter® Score methodology is refreshingly simple by comparison. Instead of asking hundreds of online survey questions and doing in-depth calculations, you’ll ask one powerful question (and a few refining ones).

Then, you’ll perform just one calculation. And you’ll get an industry standard score, ranging from -100 to +100. (Learn how to do the Net Promoter Score calculation here, use our NPS Calculator, or SurveyMonkey will calculate your NPS for you!)

In a standard customer satisfaction survey example, you might ask consumers to give specific feedback on the products and services you provide. Questions like: “How quickly did the customer service team assist you?” can help you understand what consumers really think, and as a result, these questions are very valuable.

And although there are benefits to customer satisfaction versus NPS, these sample survey questions might not provide you with all of the detail you need to improve your business.

Why? Because people who are satisfied might still leave. That’s right. They might appreciate your speed and your products and your price. But, they might be just as willing to switch to another company if they get a better deal. In other words, they may like you, but they may like others more.

The Net Promoter Score Bain developed in 2003 is designed to ask something a lot different. Instead of asking if your customers are happy, you’re asking your customers if they’re promoters of your company. You’re trying to determine if your customers are willing to speak up and speak out about your brand. In essence, you’ll see how many of the people you work with right now are willing to be brand advocates.

The math you do at the end of the questionnaire will provide you with one number that will show you just how many of your consumers are willing to do that advocacy for you. Here’s how it works.

The NPS sample survey starts with one very basic but very powerful question: “How likely is it that you would recommend this company to a friend or colleague?”

We’re cutting right to the chase here, asking people straight up if they intend to work as advocates, or if they don’t really plan on spreading the good news about your products or services.

This isn’t a yes/no question, either. Participants are asked to grade their responses on a scale from 0 to 10, with low scores indicating a complete lack of willingness to work as an advocate, and 10 as a very high likelihood of working as an advocate.

The follow-up questions allow you to gather just a bit more data. Here, you’re asking open-ended survey questions that could help you to understand why people are willing to speak up for you, and what might need to change in order to make advocacy more likely. You might ask:

The open-ended nature of this online poll will give you the data you need in order to push your products, services, or approach in a different direction. But, there’s one more thing you can do with these results in order to help your company. And yes, there is a little math involved.

In order to come up with a score, or percentage, of promoters, you’ll return to the answers consumers provided to your original question. Specifically, you’ll be looking at that little 0 to 10 grade they gave your company when asked if they’d promote it. Those grades allow you to segment your consumers into three groups:

Once you’ve segmented your respondents into groups, you’re ready for math. Thankfully, it’s pretty easy. A Net Promoter Score definition, in simplest terms, is the percentage of detractors subtracted from the percentage of promoters. You’ll do this by following this simple formula:

(Number of Promoters — Number of Detractors) / (Number of Respondents) x 100

That’s it!

This simple calculation will allow you to see how many consumers are fans of your company, willing to give it a shout out.

A Net Promoter Score provides a good benchmark for you to gauge which percentage of your customers are brand advocates. Just as important, a NPS also reveals who isn't and, even better, what percentage of customers can easily become one. Furthermore, a NPS can also gauge trends. With just one number, you can easily assess how well your business is performing against competitors and even the industry, along with companies associated with yours. Overall, a Net Promoter Score is a smart way to gauge how the economy is doing. 

Now that you know what a Net Promoter Score is, the methodology behind it, and the formula, you'll need to learn how to ask the right questions to get the most relevant feedback possible. Get access to SurveyMonkey's bank of researched questions. 

You'll also need a product to help you organize and analyze feedback. Sign up to develop feedback and insights on an AI-powered platform.

Having the right solution to help you interpret your Net Promoter Score is key to good marketing. Even with this simple formula provided above, it's still important to learn exactly what these numbers mean and how they can work for you. According to one of our studies, 20% of customers represent Passives. This number means that you have the opportunity to increase your Promoters by 20%. Finding out exactly how you can achieve this depends on the questions you ask and how you use that information to improve your customers' experience. Let's look at this approach in steps:

To get a NPS, you must ask the right questions in the right way, which means if you're trying to gauge a customer's response, then it's best to stay away from binary yes or no questions. The best approach for a score is to use a rating scale that measures a customer's satisfaction level. Rating scales are usually 0–5 or 0–10, with zero representing "not satisfied" to 10 representing "very satisfied." The feedback you'll collect will be quantitative, allowing you to analyze results mathematically. 

Once your customers have completed the survey, you will have data ranging from 0–10. This step is the part where you'll need to categorize feedback into Detractors, Passives, and Promoters. With the right experience management solution, your responses can be automatically filtered into these three categories and save you tons of time. 

This step is just a matter of adding up all responses whose answers range from 1-6 and listing them as Detractors. Then, you'll add up all of the responses whose answers are either 7 or 8 and label those as the Passives. The remaining answers should be 9 and 10. The sum of those numbers is the Promoters. 

It's worth repeating the scores are the difference between Promoters and Detractors that are then divided by the total number of survey respondents. The next step is to plug in the sum of those numbers into the NPS formula according to its respective labels. Calculating the NPS formula is another step that can be automated using the right kind of AI-powered solutions. Your number will determine the next steps you'll need to take to improve and sustain your business's health. 

Think of a Net Promoter Score as a grade. However, the NPS calculation formula is a little different from academic grading because a NPS can go below 0. If your NPS ends up being a negative number, then it's clear that your organization needs to address several issues. If your NPS ranges between 0–30, your business is not doing badly, but it's not exactly great either, which means there's room for improvement. If your NPS is higher than 30, your business is doing pretty good, but again, there's always room to improve. If your NPS is 70 and over, you can take comfort in knowing you have many Promoters. 

Here's a quick go-to NPS grading scale:

While asking good questions is a great way to determine customer satisfaction, another way is to analyze your website's analytics. For example, assessing the number of times customers have viewed your webpage, the amount of time spent on a webpage, and how many URL referrals you have can gauge how involved people are with your business. Even how quickly each page loads can have a positive or negative effect on customer experience.

The detail you get in follow-up questions will be a key part of the marketing changes you do and do not make for your company. That much is clear. But the numeric score you get after doing a little basic math is intensely powerful. It’s a benchmarkable number you can use, year after year, to track your progress. And, you can even use that number to compare your success with the success of your competitors.

And it all starts with one simple question. Click here to get started.

NPS®, Net Promoter® & Net Promoter® Score are registered trademarks of Satmetrix Systems, Inc., Bain & Company and Fred Reichheld.