How NPS is worked out
Everyone answers one question on a 0 to 10 scale. People who answer 9 or 10 are promoters, 7 or 8 are passives, and 0 to 6 are detractors. The score is the percentage of promoters minus the percentage of detractors, so it runs from −100 to 100. Passives count toward the total but not toward either side.
Example: 50 answers, 25 promoters (50%), 15 passives and 10 detractors (20%). NPS = 50 − 20 = 30.
What is a good NPS for software?
Anything above zero means more fans than critics. Treat published industry averages with care, because they mix very different products and survey methods. The number that matters most is your own score next quarter compared with this one, and the comments behind it.
Ask inside your app, not by email
Email surveys reach the people who still read your emails. An in-app survey reaches people while they are using the product, and the answer can sit next to what they actually did. Here is how to run one, or try OnboardingTours free: the survey card, the score and the comments are built in.