Revenue lost to churn over 12 months — and what 1% lower would save.
Inputs
Monthly recurring revenue right now
% of MRR lost to cancellations each month
From new subscriber acquisition
Show impact if churn dropped by this much
Results — 12 month projection
Revenue lost to churn—
MRR in 12mo (current)
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MRR in 12mo (improved)
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Annual Δ at improved churn
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Month-by-month projection
Month
Start MRR
Churned
New
End MRR
About this calculator
Churn is the leaky bucket problem of every subscription business. You can pour water in (acquire new subscribers) faster and faster, but if the bucket leaks at 8% per month you spend most of your effort just maintaining MRR rather than growing it. This calculator visualizes exactly how much revenue churn extracts and what a small reduction would save.
The compounding nature of churn is the key insight. Losing 5% per month sounds like 60% annual loss, but the math is multiplicative: 0.95^12 = 0.54. That means after 12 months only 54% of your starting MRR remains from the original cohort — even before considering that customers who survive 12 months are also subject to monthly churn going forward. Reducing churn from 5% to 4% changes 12-month retention from 54% to 61%, which on a $1M ARR base is $70,000 in annual revenue saved without acquiring a single new customer.
This is why mature subscription companies obsess over retention metrics. The math says retention investment compounds while acquisition investment is linear. Cutting churn 1% is roughly equivalent in 12-month MRR impact to acquiring 15-20% more customers — but retention investments (better onboarding, dunning campaigns, lifecycle email) typically cost a fraction of new-customer acquisition.
Use this tool alongside the Subscriber LTV Calculator (which directly factors churn into lifetime value) and the Cohort Retention Visualizer (which shows decay curves by signup cohort). The three together give a complete picture of subscription health — current state, lifetime value implications, and retention curve shape over time.
Frequently asked questions
How is churn revenue impact calculated?
Each month, churned customers represent lost MRR equal to (churn rate × MRR at start of month). Cumulative impact projects this forward 12 months while also factoring in new MRR added from acquisition. The calculator runs a month-by-month simulation rather than a static formula because churn compounds — losing 5% in month 1 affects what is available to churn in month 2.
Why does a 1% lower churn rate make such a big difference?
Because churn compounds. The difference between 5% and 4% monthly churn is not 1% over a year — it is roughly the difference between 46% annual retention and 56% annual retention, which translates to 20%+ more revenue at year-end on the same MRR base. This is why retention investments often have higher ROI than acquisition investments at scale.
What counts as a "good" monthly churn rate?
For consumer subscriptions: under 5% monthly is good, under 3% is excellent, under 2% is best-in-class. For B2B SaaS: under 2% monthly is acceptable, under 1% is good. For low-priced consumer subscription boxes ($20-30/mo) churn often runs 8-12% in the first 90 days then stabilizes around 5%. Annual contracts dramatically lower effective monthly churn.
Should I include voluntary and involuntary churn separately?
Yes if you can. Voluntary churn (active cancellation) signals product-market fit issues. Involuntary churn (failed payments, expired cards) signals operations issues — and is much easier to fix with dunning campaigns and card-updater services. A typical subscription business sees 30-40% of total churn coming from involuntary causes, which means recovering even half of that often produces a 1-2% absolute reduction in monthly churn.
How do new customers offset churn in this model?
Each month the model adds your "new MRR" input (new subscribers × ARPU) on top of the churn loss. Net MRR change = New MRR − Churned MRR. If new MRR > churned MRR you grow; if churned MRR > new MRR you contract even with strong acquisition. The break-even is where new MRR equals churn losses — known as your "treadmill speed."