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Churn rate calculator

Enter customers at the start of a period and how many you lost. Add revenue numbers if you want revenue churn too. It works out the period churn rate, the monthly and annual equivalents, and retention. Nothing you type leaves your browser.

The formulas

Churn rate = customers lost / customers at start
Retention rate = 1 - churn rate
Monthly churn from a longer period = 1 - (1 - period churn) ^ (1 / months)
Annual churn from monthly = 1 - (1 - monthly churn) ^ 12
Revenue churn = revenue lost / starting revenue

Don't count new customers won during the period in the starting number. And note that 2% a month is not 24% a year: compounding makes it about 21.5%.

A worked example

Start of quarter: 400 customers | Lost: 12
Quarterly churn: 12 / 400 = 3.0%
Monthly equivalent: 1 - (0.97)^(1/3) = about 1.01%
Annual equivalent: 1 - (0.97)^4 = about 11.5%

The number tells you how much. It doesn't tell you why. Log the why with the churn reason code list, see how to run a churn analysis, and check revenue retention with the NRR and GRR calculator. To spot which accounts are likely next, try the churn risk calculator.