Churn Rate Calculator

Customer attrition, its mirror image retention, and the average lifetime a customer represents all flow from a single rate. Tracking them lets a business spot trends early, sketch out future revenue, and act before losses compound. In a crowded market these numbers underpin whether growth is actually sustainable.

Churn rate is the number of churned customers divided by total customers at the start of the period, multiplied by 100. Retention is whatever remains after subtracting that from 100%. Average customer lifetime follows from dividing 1 by the monthly churn rate expressed as a decimal, giving a rough sense, in months, of how long the typical customer sticks around. If you pick a quarterly or annual period, the calculator first converts the churn to its monthly equivalent, 1 − (1 − rate)^(1/3) or 1 − (1 − rate)^(1/12), and it compounds the monthly rate to show annual churn as 1 − (1 − monthly rate)^12.

Consistency in the time window matters, so pick monthly, quarterly, or annual and hold to it, and settle on a firm definition of what counts as a churned customer. Folding customers acquired mid-period into the starting total is a frequent error that quietly props up retention. Seasonality deserves a second look too, since heavy churn in December can be perfectly ordinary for certain businesses.