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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Use this result
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What does this calculator estimate?
A subscription churn impact calculator projects how churn and new signups shape your customer base and revenue. Enter starting customers, monthly churn, new customers, and ARPU.
- Required new = churn × customers
- 5% monthly churn needs 50 new per 1,000 just to hold
- Churn compounds — small rates add up fast
How churn compounds
Churn is a leak in the bucket: 5% monthly churn means losing 5% of remaining customers every month. Without matching new signups, the base decays exponentially — 5% monthly churn halves the base in ~14 months. The calculator shows the projection month by month.
Limitations to watch for
Churn isn't constant — it varies by cohort and improves with retention work. New customer volume and ARPU are inputs you must estimate. The model is monthly and linear; real signups fluctuate.
How to use it in practice
Enter your real churn and ARPU, then test scenarios: what happens if churn drops from 5% to 3%? What new-customer volume is needed to grow? Use the results to justify retention investment — keeping a customer is usually cheaper than acquiring one.
- Enter starting customers, monthly churn, and ARPU.
- Enter new customers per month.
- Read the projected base and revenue over time.
What churn costs
Churn is the share of subscribers who cancel each period. A 5 percent monthly churn on 1,000 subscribers at $20 monthly loses 50 subscribers and $1,000 in MRR this month — and the lost revenue compounds because those subscribers never return.
Churn and growth math
Net growth = new subscribers − churned. At 10 percent monthly new and 5 percent churn, the base grows 5 percent monthly — about 80 percent annually. Cutting churn to 3 percent nearly doubles that growth rate. The calculator shows the compounding.
Lifetime value connection
LTV = ARPU ÷ churn: at $20 monthly and 5 percent churn, LTV is $400. Halving churn doubles LTV — the highest-leverage subscription metric. The calculator returns LTV from churn so retention improvements are priced.
A worked example
1,000 subscribers, $25 ARPU, 4 percent monthly churn: 40 lost monthly, MRR erosion $1,000/month, LTV $625. Improving retention to 3 percent raises LTV to $833 and slows the erosion by 25 percent. The calculator shows both scenarios side by side.
Annual vs. monthly churn
Annual churn is the monthly rate compounded: 4 percent monthly is about 39 percent annually. Comparing plans on annual churn avoids the misleading small monthly number.
How this calculator works
Formula
Monthly churn requires churn × customers new customers/month just to hold steady. The tool projects the customer base and revenue month by month given churn, new customers, and ARPU.
Worked example
1,000 customers at 5% monthly churn need 50 new customers per month just to stay at 1,000 — anything less and the base shrinks.
Assumptions to verify
- Churn, new customers, and ARPU are constant monthly rates.
- No seasonality or one-time events are modeled.
- Revenue is ARPU × customer count per month.
Frequently asked questions
What is churn?
The rate at which customers cancel or stop paying — 5% monthly churn means losing 5% of customers each month.
How many new customers do I need to offset churn?
Churn × customer count per month. 5% of 1,000 = 50 new customers monthly just to hold steady.
How fast does churn shrink the base?
Exponentially: at 5% monthly churn, the base halves in about 14 months without new signups.
How do I reduce churn?
Improve onboarding, deliver the core value faster, monitor usage drops, and reach out before cancellation.
What is ARPU?
Average revenue per user — total subscription revenue divided by customer count. ARPU × customers = monthly revenue.
Why is retention cheaper than acquisition?
Acquisition costs marketing and sales spend; retention costs product improvements and support — usually a fraction of the price.
What's a healthy churn rate?
Under 2–3% monthly is strong for consumer subscriptions; B2B should be lower. It depends on your market.
What is churn rate?
The percentage of subscribers who cancel in a period — usually monthly.
How does churn affect revenue?
Each churned subscriber's revenue is lost forever; the impact compounds.
What is LTV and how does churn affect it?
LTV = average revenue per user ÷ churn — lower churn means higher LTV.
What is a good churn rate?
Under 5% monthly is healthy for most SaaS; under 2% is excellent.
Cite this tool
BoringToolsKit. “Subscription Churn Impact Calculator.” boringtoolskit.com/subscription-churn-impact-calculator/ (reviewed 2026-08-25). Free to reference in articles, syllabi, and answer posts with a link.
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