Formula
% Promoters (9-10 score) - % Detractors (0-6 score)
How to measure
Survey customers with 'How likely are you to recommend this to a friend?' on a 0-10 scale, then subtract the percentage of detractors from the percentage of promoters.
Why track it
NPS gives a quick, comparable pulse on customer sentiment across time periods and against industry benchmarks.
Example
A survey with 60% promoters and 15% detractors produces an NPS of 45.