Net Promoter Score (NPS) is a metric used to gauge customer loyalty and satisfaction by asking a single question: "How likely are you to recommend our product/service to a friend or colleague?" Respondents answer on a scale from 0 to 10, with scores categorized into Promoters (9-10), Passives (7-8), and Detractors (0-6). The NPS is then calculated by subtracting the percentage of detractors from the percentage of promoters.