What this calculator measures
Customer churn measures how many customers from the beginning of a period were lost during that period. New customers belong in ending-customer and net-growth calculations, but not in the denominator for gross churn. Mixing the two can make retention look better than it was.
This calculator reports gross churn, retention of the starting cohort, ending customers and net change. Use consistent definitions for active, paused, cancelled and reactivated accounts before comparing periods.
How to use the Customer Churn Calculator
- Enter customers active at the beginning of the period.
- Enter customers lost and new customers acquired during that period.
- Review gross churn, retention, ending count and net growth separately.
Customer churn = customers lost ÷ customers at start × 100
Retention equals starting customers minus lost customers, divided by starting customers. Ending customers add new customers after losses.
Worked example
Starting with 1,000 customers, losing 30 and adding 80 produces 3% gross churn, 97% retention and 1,050 ending customers.
Assumptions and limitations
- Customer churn is different from revenue churn and net revenue retention.
- Define cancellations, pauses and reactivations consistently.
- Short periods can be noisy for businesses with small customer counts.
- Cohort analysis is needed to understand churn by acquisition period or segment.