Net promoter score (NPS) is a powerful tool for gathering invaluable insights into how your brand and the experience it delivers are perceived. Understanding the formula associated with NPS and, more importantly, how to accurately calculate your score will help you better understand your customer or employee experience. 

What is Net Promoter Score (NPS)?

A net promoter score is a specific metric that highlights the overall performance of your customer or employee experience. The score is based on your customer’s likelihood to recommend your product, service, or organization.  

NPS was developed so that companies could more easily quantify otherwise qualitative responses — it’s difficult to pull data from an emotion, right? Yet, emotion can be a powerful indication of your company’s ability to make customers happy. NPS makes this process possible by attributing emotions to certain outcomes, such as: 

• Customer happiness, which can result in customer loyalty or customer acquisition due to word-of-mouth recommendations
• Customer dissatisfaction, which can result in poor customer retention and loss of sales over time

What is the Net Promoter Score formula, and how does it work?

To calculate NPS, you take the total percentage of promoters (those who would likely recommend your company) and subtract the total percentage of detractors (those who aren’t likely to recommend your company). The result is your net promoter score. 

Total % of Promoters (-) Total % of Detractors = (Net Promoter Score)

Confused on how to find the total percentage of both promoters and detractors? Let’s dive in. 

Using the Net Promoter Score formula

Net promoter scores are based on a scale, from -100 to 100, with 100 being the ideal score, meaning 100% of people would likely recommend your company. Let’s learn how to efficiently and accurately calculate where you are on the NPS scale. 

1. Survey customers

The NPS formula is rooted in a single question — one most people have encountered during experiences with websites, retail brands, and more:

On a scale of 1-10, how likely would you be to recommend this company, product, or service to a friend?

The NPS formula delivers variations of the above sentence in a given NPS survey and has participants quantify their emotion on a scale of 1–10. 

Variations of NPS questions may include: 

• Based on your interaction with our customer service team, how likely are you to recommend our company? 

• Following the purchase of your new [product], how likely are you to recommend our product? 
• Based on your initial trial of our software, how likely are you to recommend this product to others? 

A best practice is to create a survey composed of similar questions. Aim to create targeted questions that are specific to a certain service experience, particular product, or experience had by a certain industry. This will help you uncover targeted responses and specific experiences. 

2. Categorize responses

Participants give each question on your NPS survey a score on a scale of 1–10. Based on the number they provide, they will be categorized into one of three categories: 

From here, you will be able to understand how many promoters and detractors you have to accurately calculate your NPS. 

3. Find the percentage of promoters vs. detractors

In order to calculate your NPS, you need to find the percentage of promoters and detractors. Simply factor in the amount of promoters (those who provided a score of 9–10) against the total number of respondents. Be sure to turn decimals into percentages to make the formula easier. 

Similarly, factor in the amount of detractors (those who provided a score of 0–6) against the total number of respondents. This will provide your total percentage of detractors.

4. Calculate your final NPS using the Net Promoter Score formula

Lastly, plug in your promoter and detractor percentages into the net promoter score formula. 

For example, if you surveyed 100 people and you had 70% promoters and 10% detractors, your NPS formula would look something like this:

70% (-) 10% = 60%

Your final NPS would be 60, on a scale from -100 to 100. 

How to build a survey that customers respond to

You can’t accurately calculate your net promoter score without a sizable amount of responses to translate into the respective promoter and detractor buckets. Build a survey that customers are likely to respond to in order to effectively gather information. 

Tech protection and service company, Likewise (formerly Brightstar), divulged its best practices for creating impactful NPS surveys, which doubled its survey response rate. 

• Set expectations for the survey: Be transparent about how the survey is going to be used to improve a particular operation or experience. 
• Put your first question in the survey invitation: Give users a chance to begin the survey immediately to ease them into the process. 
• Don’t put NPS first: When people think of surveys, they think of work. Coming out and asking customers to complete an NPS survey can feel like asking customers for a favor, one in which they won’t get much in return. 
• Make the survey a one-pager: Limit questions to a single page (no more than five questions, if possible!) to prevent the survey from feeling like a huge task. 
• Vary the questions you ask among customers: Keep a few key questions as a constant access to the surveys, but switch out the rest of them to provide variety among each survey taken. 
• Rotate who gets the survey: To prevent survey fatigue, don’t request a survey from the same customer every single time. This is especially important if you request surveys on a regular basis. 
• Ask questions along the buyer’s journey: Each section of the buyer’s journey is equipped with its own unique touchpoints. Structure surveys around these specific experiences.
• Be data-driven and adapt your outreach methods to meet customers where they are: Emails not getting opened? SMS (text) messages might produce a greater response rate. Likewize reported that text surveys generated response rates of about 35% to 40%, compared to only 30% to 35% for email. 

Developing a survey that customers want to respond to can provide another tool in your repertoire of methods for measuring customer loyalty and promoting customer acquisition and retention long-term.