Measure sauna client retention without letting newly acquired clients inflate the result. Enter opening clients, new clients, and closing clients to isolate the retained opening base, period churn, and an equivalent monthly churn estimate. The revenue context also shows how much recurring monthly revenue is attached to those retained clients.
The retained count is capped between zero and the opening client base.
Retention isolates the share of the opening client base that remained active, rather than treating newly acquired clients as retained.
Use consistent definitions of active client at both dates. Reactivations may need to be treated separately from new clients.
Starting with 200 clients, adding 35, and ending with 205 leaves 170 retained opening clients. Retention is 85.0% and period churn is 15.0%.
They were not part of the opening base, so subtracting them isolates clients who could actually be retained.
This calculator caps retained opening clients at the starting count to prevent acquisition or data timing from overstating retention.
Count them consistently as new or separate from ending clients if they were inactive at the start.
Use a period that matches the service cycle, then enter its length in months for monthly normalization.
For the defined opening cohort in this calculator, period churn is the complement of retention.
| Input | Counting rule |
|---|---|
| Starting clients | Active at the opening date |
| New clients | First activated during the period |
| Ending clients | Active at the closing date |