Calculated as 1 / monthly churn rate, or 12 / annual churn rate. With a 10% annual churn, average customer lifetime is 120 months (10 years). With 25% annual churn, it's 48 months (4 years). LTV = ARPU × Gross Margin × Lifetime - so cutting churn 25%→10% extends LTV by 2.5×. The CS team's most leveraged input.
12 / Annual Churn Rate10% annual churn → 12 / 0.10 = 120 months (10 years).
See how public B2B SaaS companies disclose this metric, with full historical time series.