Churn rate

Churn rate (also known as attrition rate, turnover, customer turnover, or customer defection) is a measure of the proportion of individuals or items moving out of a group over a specific period. It is one of two primary factors that determine the steady-state level of customers a business will support.

Churn is widely applied in business for contractual customer bases. Examples include a subscriber-based service model as used by mobile telephone networks and pay TV operators. Churn rate can also be the input into customer lifetime value modeling and used to measure return on marketing investment with marketing mix modeling. The term comes from the image of agitation of cream in a butter churn.