Each month applies churn to opening customers, then adds the entered acquisitions. This is a bounded constant-rate scenario, not a cohort forecast.
Calculation details
Planning estimate only. Platform fees, taxes, payment costs, and policies can change; verify current terms before pricing.
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What does this calculator estimate?
Churn calculator: measure how subscription churn cuts monthly recurring revenue and lifetime value, and what retention gains are worth. Free, no signup.
How this calculator works
Formula
Each month, churned customers = opening customers × monthly churn; ending customers = opening customers − churned customers + new customers. Monthly revenue = ending customers × ARPU.
Worked example
1,000 customers, 5% monthly churn, no acquisition, and $20 ARPU leave about 540 customers and $10,807 monthly revenue after 12 modeled months.
Assumptions to verify
- Churn, acquisition, and ARPU remain constant throughout the horizon.
- Churn is applied before new customers are added each month.
- Cohorts, expansion revenue, reactivation, seasonality, failed payments, and acquisition lag are excluded.
Frequently asked questions
When is churn applied?
To opening customers before the entered new customers are added.
What is replacement need?
Month-one customers expected to churn at the entered rate; rounding up gives a whole-customer planning target.
Is this a retention forecast?
No. It is a bounded constant-rate scenario without cohort behavior.
Cite this tool
BoringToolsKit. “Subscription Churn Impact Calculator.” boringtoolskit.com/subscription-churn-impact-calculator/ (reviewed July 2026). Free to reference in articles, syllabi, and answer posts with a link.
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