KKPI Formulas
SaaS KPI Formula

Customer Churn Formula

Customer churn measures lost customers as a percentage of the starting customer base.

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Simple formula

Customers Lost / Customers at Start

The formula uses these inputs:

  • Customers Lost: enter your value in the calculator or spreadsheet.
  • Customers at Start: enter your value in the calculator or spreadsheet.

Excel formula

Use this Excel formula as a starting point. Replace the sample cell references with the cells in your worksheet.

=IFERROR(B2/C2,0)

Google Sheets formula

In most cases, the Google Sheets version uses the same structure as Excel.

=IFERROR(B2/C2,0)

Power BI DAX measure

Use this DAX pattern as a starting point and rename measures or columns to match your Power BI model.

Customer Churn =
DIVIDE(
    [Customers Lost],
    [Customers at Start]
)

SQL example

This generic SQL pattern can be adapted to your warehouse table names and column names.

SELECT
    /* replace with your formula */ AS customer_churn
FROM kpi_data;

Customer Churn calculator

Result—

How to interpret Customer Churn

Use this KPI with trend data, targets, and related metrics. A single value is less useful than a consistent definition tracked over time.

Important: KPI definitions can vary by company, accounting policy, analytics platform, or reporting standard. Keep the definition consistent when comparing periods.

Common mistakes

  • Mixing different time periods in the numerator and denominator.
  • Using totals that do not match the KPI definition used by your company.
  • Comparing results across teams or industries without context.

Related KPI formulas

Frequently asked questions

What is the Customer Churn formula?

The common Customer Churn formula is: Customers Lost / Customers at Start.

How do you calculate Customer Churn in Excel?

Use this Excel formula pattern: =IFERROR(B2/C2,0). Replace the cell references with your own data.

Can this KPI be calculated in Power BI?

Yes. Use the DAX measure on this page as a starting point and adjust table and column names to match your model.