Direct answer
Customer retention measures how much of a starting customer cohort remains, while customer churn measures how much leaves; they complement each other only when definitions and cohort treatment align.
What this calculation tells you
Retention and churn summarize continuity within a defined customer relationship. They can reveal product, service and contract patterns but do not explain the cause of departure.
A business can retain most customers while losing a large share of revenue if a few high-value accounts leave. Expansion can also make net revenue retention exceed 100% even with customer churn.
Where it is used
Subscriptions
Track account or subscriber continuity by acquisition cohort and plan.
B2B services
Separate logo loss from contract-value expansion and contraction.
Memberships
Measure renewals using the actual eligibility and grace-period rules.
Repeat retail
Define an inactivity window before labeling a customer churned.
Common situations
- New customers mask losses in the ending total.
- One large account cancels while many small ones stay.
- Monthly and annual plans have different renewal opportunities.
- A changed inactivity rule shifts reported churn.
Build a clean starting cohort
Identify customers active and eligible at the start. Treat new acquisitions, reactivations, pauses, migrations and involuntary payment failures consistently.
Match period to buying rhythm
Monthly churn is natural for monthly subscriptions but can be misleading for infrequent retail purchases. Use a window suited to expected behavior.
Add revenue and segment views
Track customer count alongside gross and net revenue retention. Segment by tenure, plan, channel and customer type where sample size permits.
Investigate causes outside the percentage
Cancellation reason, usage, support, product fit, pricing and payment failure require additional evidence. Do not infer causation from the rate alone.
- Document eligibility.
- Report counts and rates.
- Keep reactivation separate.
Practical questions
Frequently asked questions
Do retention and churn always add to 100%?
They can for one aligned starting cohort and binary outcome, but pauses, reactivations, multiple definitions and timing can break that shortcut.
Should new customers be included in retention?
Not in ordinary starting-cohort retention; report acquisition separately.
What is the difference from revenue churn?
Customer churn counts relationships, while revenue churn weights the monetary amount lost.
Further reading
Authoritative sources
Use these primary and professional resources to check definitions, conventions, or requirements that may extend beyond this guide.