Churn rate measures revenue lost from customers who cancelled. Dollar-weighted (vs logo churn which is count-weighted). Often expressed annualized. The complement of churn is gross retention. A 10% annual churn rate means that ignoring expansion, you'd lose 10% of starting ARR by year-end. Strong B2B SaaS targets <8% annual gross churn.
Revenue churned / Starting recurring revenue, often annualizedStarting MRR $100K, churned MRR $2K = 2% monthly churn = ~22% annualized.
See how public B2B SaaS companies disclose this metric, with full historical time series.