Customer Support KPI

Net Promoter Score Formula

Learn what Net Promoter Score means, how to calculate it in Excel, and how to recreate the same KPI as a Power BI DAX measure.

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Quick answer

Net Promoter Score is calculated as:

Promoter % - Detractor %

Use this Excel version when your inputs are on row 2:

=B2 - C2
Example result48
FormatScore or percentage points
Typical chartKPI card for the latest value, plus a trend line over time.

What is Net Promoter Score?

Net Promoter Score summarizes survey or feedback results into one number. It should be read together with comments, sample size, and trend over time.

Customer support KPIs track service speed, resolution quality, workload, satisfaction, and support cost.

Beginner tip: A KPI is not just a formula. It is a number used to make a decision. Before adding it to a dashboard, write down the definition, time period, owner, target, and data source.

Real-life example

Imagine a support manager reviewing team performance. The team adds the inputs for Net Promoter Score to a support operations dashboard, calculates the KPI for the current month, and compares it with the previous month and target. In the sample below, the result is 48. That number becomes useful when everyone uses the same formula each month.

Excel cellInputWhat it meansSample value
B2Promoter %a percentage input written as a decimal in Excel, such as 60% as 0.600.6
C2Detractor %a percentage input written as a decimal in Excel, such as 60% as 0.600.1
ResultNet Promoter ScoreOutput of the KPI formula48

How to calculate Net Promoter Score in Excel

  1. Create one row per reporting period, team, product, campaign, location, or customer segment.
  2. Add one input per column. Do not combine inputs in the same cell.
  3. Paste the Excel formula in the KPI result column.
  4. Format the result as Score or percentage points.
  5. Copy the formula down the table and compare the result against target, previous period, and trend.
Quality check before publishing:
  • Use the same date range for every input.
  • Confirm that the denominator is not blank or zero.
  • Document whether the KPI is calculated before or after discounts, refunds, taxes, returns, or cancellations.
  • Keep the definition stable so reports remain comparable over time.

Power BI DAX measure

If you also report this KPI in Power BI, create a measure instead of hard-coding the calculation in a visual. Replace the measure names below with the names used in your model.

Net Promoter Score = [Promoter %] - [Detractor %]

For best results, build base measures first, such as revenue, cost, customers, orders, or tickets, and then build the KPI measure from those base measures.

How to read the result

Higher is usually better, because this KPI normally represents revenue, efficiency, quality, retention, productivity, or successful outcomes.

Do not read the KPI alone. A single value can be misleading without a target, trend, segment, and business context. For example, the same result may be good for one product line but poor for another.

Useful comparisons

  • Current month versus previous month.
  • Actual result versus target or budget.
  • By channel, product, customer segment, team, or location.
  • Rolling average over several periods to smooth one-off spikes.

Common mistakes

  • Mixing time periods, such as monthly cost with quarterly revenue.
  • Using a total when the KPI should be segmented.
  • Changing the formula definition after the dashboard is already in use.
  • Comparing two teams that collect the inputs differently.
  • Ignoring blanks, zeros, refunds, cancellations, or duplicate records.