Net Promoter Score Calculator Formula

Understand the math behind the net promoter score calculator. Each variable explained with a worked example.

Formulas Used

Net Promoter Score

nps = (promoters + passives + detractors) > 0 ? ((promoters / (promoters + passives + detractors)) - (detractors / (promoters + passives + detractors))) * 100 : 0

Promoter %

promoter_pct = (promoters + passives + detractors) > 0 ? (promoters / (promoters + passives + detractors)) * 100 : 0

Detractor %

detractor_pct = (promoters + passives + detractors) > 0 ? (detractors / (promoters + passives + detractors)) * 100 : 0

Variables

VariableDescriptionDefault
promotersNumber of Promoters (scored 9-10)60
passivesNumber of Passives (scored 7-8)25
detractorsNumber of Detractors (scored 0-6)15

How It Works

How to Calculate Net Promoter Score

Formula

NPS = % Promoters - % Detractors

NPS is based on one question: "How likely are you to recommend us?" Responses fall into three groups: Promoters (9-10), Passives (7-8), and Detractors (0-6). The score ranges from -100 (everyone is a detractor) to +100 (everyone is a promoter). Passives are excluded from the final calculation but still factor into the denominator.

Worked Example

Out of 100 survey responses: 60 are promoters, 25 are passives, and 15 are detractors.

promoters = 60passives = 25detractors = 15
  1. 01Promoter % = 60/100 = 60%
  2. 02Detractor % = 15/100 = 15%
  3. 03NPS = 60% - 15% = 45

Ready to run the numbers?

Open Net Promoter Score Calculator