How this calculation works
The loss rate concerns the opening cohort only. Net additions still active at the end are added separately to determine ending size and net count growth. This is a count model; it does not infer revenue churn, downgrades, upgrades or the value of individual customers.
Churn = opening-cohort losses / opening customers; ending = opening − losses + net additionsA worked example
From 1,000 opening customers, 50 losses give 5% churn. With 100 net active additions, the ending count is 1,050 and net growth is 5%.
Good to know
A transparent arithmetic model using your inputs. Example prices, rates and multiples are demonstrations, not benchmarks or offers. No tax, exchange-rate conversion, live account access or automatic attribution is supplied. Monetary display is rounded; calculations retain additional precision.
Keep the opening cohort separate from additions
Opening-cohort churn counts losses among the customers who were active at the period start. New customers are handled separately. Mixing gross new sign-ups and cancellations from different cohorts can change the meaning of the fraction.
The additions input is net additions still active at period end. If newly added customers already cancelled before the end, they should not remain in that ending-active addition count.
Membership revenue turns a supplied member count and price into a revenue scenario. Cohort retention and net new members must be tracked separately when forecasting later periods.
Customer retention is not revenue retention
Customers can have different prices, discounts and plan sizes. Losing five customers does not tell you the lost revenue share without knowing their value. Upgrades and downgrades can also change revenue while the customer count stays the same.
A business can have positive net customer growth and still lose a meaningful portion of its opening cohort. The tool shows churn, retention and ending count separately so new additions do not hide opening-cohort losses.
A few questions, answered
Can opening-cohort losses exceed the opening count?
No. That combination is rejected because it cannot describe this cohort definition.
Does zero churn guarantee stable revenue?
No. Prices, usage, collection and plan changes can affect revenue independently of customer-count churn.