Net Promoter Score (NPS®) is a proven methodology for measuring customer loyalty through first-hand feedback. Net Promoter Score is a popular customer experience metric because it is simple, effective, and correlated to revenue growth.

NPS is calculated by asking an initial survey question, usually on a 0–10 rating scale. Then, the accumulated scores are graded. 

This number determines how customers perceive a company. Fred Reichheld, a partner at Bain & Company, developed Net Promoter Score in 2003 after analyzing how traditional customer satisfaction survey questions correlate to consumer behavior. 

The carefully phrased survey question, “How likely are you to recommend [company] to a friend?” is now utilized by millions of brands worldwide.