Net Promoter Score (NPS) is a management tool to measure customer satisfaction and has been shown to correlate with revenue growth relative to competitors. NPS is the percentage of customers rating their likelihood to recommend a company, a product, or a service to a friend or colleague as 9 or 10 ("promoters") minus the percentage rating this below 6 ("detractors") on a scale from 0 to 10.
NPS is calculated on the customer responses to the question: How likely is it that you would recommend our company/product/service to a friend or colleague? The scoring is typically done on a 0 to 10 scale. The customers answering 9 - 10 are Promoters, the customers answering 0 - 6 are Detractors, and the customers answering 7 - 8 are Passives. Passives count toward the total number of respondents, thus decreasing the percentage of detractors and promoters and pushing the net score toward 0.