What this calculator measures
Customer churn rate measures customers lost during a period as a share of customers at the start. New customers do not belong in the churn-rate denominator because they were not present at the beginning and exposed to the full period in the same way.
Use a consistent definition of active customer and lost customer. Trial users, paused accounts, involuntary payment failures, merged accounts, and reactivations can materially change the rate if classification changes between periods.
Common use cases
Use this model when the inputs describe the same decision, period and customer or product scope.
- Measure customers lost during a stated period as a share of the starting customer base.
- Compare churn across cohorts or segments with the same active-customer and loss definitions.
- Track revenue churn and retention separately when customer value differs materially across accounts.
Formula
Use the same period and customer definition for the starting base and customers lost.
Formula breakdown
- Keep the beginning-customer and churn-event definitions consistent.
- Customer churn and revenue churn answer different questions.
Worked example
A business starts the month with 1,000 customers, loses 45, and adds 80. Customer churn is 45 ÷ 1,000 = 4.5%, retention is 95.5%, and ending customers are 1,035. Growth in total customers does not erase the underlying churn.
Scenario comparison
35 churns from 1,000 starting customers gives 3.5% customer churn.
If those 35 customers are unusually high-value, revenue churn may be much higher.
How to interpret the result
Compare like periods and segments. Monthly churn should not be compared directly with annual churn, and enterprise and self-service customer counts may behave very differently.
Customer churn and revenue churn answer different questions. Losing one large customer may produce modest logo churn but severe revenue churn, so recurring businesses often monitor both.
What a good result looks like
Lower churn is generally favorable, but useful benchmarks depend on segment and contract length.
Cohort and trend analysis is more informative than one blended rate.
Common mistakes
- Dividing churned customers by ending customers.
- Mixing voluntary, involuntary and planned churn without defining the metric.
When this metric can mislead you
Blended churn can hide severe problems in a new cohort or channel.
Short periods can be noisy in seasonal or low-volume businesses.
How to use the result in a decision
Use churn to investigate onboarding, product value, service quality and customer fit.
Segment by cohort, plan and acquisition source when sample size allows.
Assumptions and limitations
- Starting and lost customer counts use the same active-customer definition.
- The period is identical across inputs and comparisons.
- Lost customers do not exceed starting customers.
- Revenue expansion, contraction, and cohort age are not modeled.