Churn

The loss of a customer or subscriber over a defined period, expressed as a rate. Voluntary churn occurs when the customer actively cancels; involuntary churn occurs when a payment method fails or a subscription lapses due to administrative error. Silent churn describes the more insidious pattern in which a user simply stops engaging without formally closing the account. Churn rate is the inverse of retention rate and, alongside Customer Lifetime Value, is the most watched metric in subscription businesses. Reducing churn is almost always more cost‑effective than acquiring new customers, because the marginal cost of retention is a fraction of the cost of acquisition.

Example: A streaming service that reduces its monthly churn rate from 5% to 4% through a pause option increases the average customer lifespan by 25%, a gain that compounds across the subscriber base.