Churn rate

Churn rate measures how much of a customer base or how much revenue disappears over a defined period, most often a month or a year. It is effectively the inverse of retention, and it is one of the biggest drivers of customer lifetime value, since a lower churn rate directly extends how long a customer keeps generating revenue.

The basic form is churn rate = customers lost during period / customers at the start of period. Businesses with variable contract sizes usually track revenue churn instead, which nets dollars lost against dollars gained from existing customers, and often separate gross churn from net churn, where net churn can turn negative if expansion revenue from existing customers outpaces losses. Logo churn (counting accounts) and revenue churn (counting dollars) can tell very different stories for the same business.

Churn rate matters as an early warning metric and as an input to CLV models and retention analysis. Common pitfalls include comparing churn rates calculated over different period lengths, failing to separate voluntary churn from involuntary churn caused by failed payments, and reading a single period's churn rate without looking at the underlying cohort analysis behind it.