NPS (Net Promoter Score) is measure of how likely your consumers are to either promote or detract from your brand. 

The formula used to calculate this metric comes from consumer responses to the question “How likely are you to recommend us to a colleague or friend?” on a scale of 0 to 10. Consumers who provide a score of 9 or 10 are considered Promoters, while those who provide a score of 6 or lower are considered Detractors, with all others considered Neutral. 

The formula used to calculate this metric is 100 * (Number of Promoters – Number of Detractors) / (Number of Responses).