Customer Churn Rate Calculator

Replace the sample values with your own, in one currency and one reporting period. Enter percentages as whole numbers: 2 for 2%. Calculations run in your browser.

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Leave out customers acquired during the month.

Count cancellations from the starting customers only.

Reported separately. Returning customers don't reduce churn.

Illustrative calculation; verify inputs and assumptions before relying on it.

Customer churn for the month—
Reactivated customers, reported separately—

Tick the box above to see your result.

Monthly Customer Churn = Customers Lost During Month / Customers at Start of Month
Variable Meaning
Customers Lost During Month Accounts that cancelled during the month.
Customers at Start of Month Active customer accounts at the start of the month.

Worked example

Paying customers at the start of the month
100
Of those, customers who cancelled during the month
5
Customers who came back during the month (optional)
2
→ Customer churn for the month
5%
→ Reactivated customers, reported separately
2

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What Customer Churn measures

Published by 4NLab · Updated · Our methods

Customer Churn measures the percentage of customer accounts lost over a given period.

Prepare your inputs

  1. Record paying accounts active at the start of the month. Exclude free trials and customers first acquired during that month from the opening cohort.
  2. Count opening accounts that churn during the month and divide by starting accounts. Report any later reactivations separately; do not subtract returning accounts from the churned count.
  3. Enter the starting and cancelled counts in the calculator, or switch it to Annualize a monthly rate. Use the annualized output as a constant-rate scenario, then compare it with actual annual cohort retention.

Formula

Monthly Customer Churn = Customers Lost During Month / Customers at Start of Month
Variable Meaning
Customers Lost During Month Accounts that cancelled during the month.
Customers at Start of Month Active customer accounts at the start of the month.

Check the sample calculation

Worked example

Paying customers at the start of the month
100
Of those, customers who cancelled during the month
5
Customers who came back during the month (optional)
2
→ Customer churn for the month
5%
→ Reactivated customers, reported separately
2

Before using the result

  • Monthly and annual percentages are not directly comparable. Label the observation interval.
  • Annualization assumes the monthly rate stays constant; seasonal renewals or annual contracts can violate that assumption.
  • Zero churn in a small or young cohort does not establish an infinite lifetime.

A dash means the result is undefined for the inputs, such as division by zero. Review the assumptions and input errors before interpreting it.

Read the Customer Churn guide for a business scenario, interpretation, and frequently asked questions.

Check how your team defines Customer Churn before relying on the result.

Sources and methodology

The references below explain the underlying methods. Our worked scenarios use hypothetical figures; they are not company results or current market benchmarks.

Found an error or a definition that differs from your reporting? Send a correction with the page URL and the method you use.