SaaS Churn Impact Calculator
Model 24 months of MRR growth followed by revenue churn. Compare gross and net MRR, monthly gaps, and the cumulative month end gap.
How the 24 month scenario works
Enter starting monthly recurring revenue (MRR), a monthly revenue churn rate, and a monthly MRR growth rate. The simulator projects a gross MRR path with growth and a net MRR path after revenue churn for 24 months.
For each month, it applies growth to MRR first and then multiplies by one minus the revenue churn rate. The churn input represents a percentage of revenue, not the percentage of customers who leave.
The table shows each month end gross MRR, net MRR, their gap, and the cumulative sum of those gaps. Final gross and net MRR refer to month 24.
The result holds both monthly rates constant. The cumulative gap uses month end MRR differences as a monthly billing proxy, not actual invoices, collected revenue, or a cohort accounting ledger.
Step by step
- Enter starting MRR in USD and monthly revenue churn and growth as percentages.
- Compare the gross and net MRR paths and the month end gap for each of the 24 months.
- Read the cumulative gap as a repeated monthly billing proxy, not cash revenue already lost.
Worked example
Enter starting MRR of 10,000 USD, monthly revenue churn of 1%, and monthly MRR growth of 0%.
Month 1 shows 10,000 USD gross MRR, 9,900 USD net MRR, and a 100 USD month end gap. At month 24, net MRR is about 7,856.78 USD. The sum of all 24 month end gaps is about 27,821.36 USD, a billing proxy rather than collected revenue.
When to use this calculator
Use this calculator to compare how a constant monthly revenue churn rate changes a growing MRR scenario over 24 months.
Use the month by month table to inspect where gaps widen. For actual revenue accounting, use invoice and collection records rather than this MRR proxy.
Common input and reading errors
Do not enter customer cancellation percentage as revenue churn unless it represents the same share of MRR. Customer counts and revenue can change at different rates when account sizes vary.
Do not read the cumulative month end gap as actual cash lost. It is a repeated monthly billing proxy and does not use invoice timing or collections.
Monthly MRR formulas
For each month m from 1 through 24:
gross MRR_m = starting MRR × (1 + monthly growth)^m
net MRR_m = starting MRR × ((1 + monthly growth) × (1 − monthly revenue churn))^m
month end MRR gap_m = gross MRR_m − net MRR_m
cumulative gap = sum of month end MRR gaps from month 1 through month 24
Growth and churn percentages are divided by 100 before use.
Growth is applied first each month, then revenue retention. This multiplicative convention differs from MRR Runrate, which combines growth and churn additively. The cumulative gap treats every month end MRR difference as one month of billing for comparison; it is not an invoice or cash collection total.
Scope and limitations
This is a constant rate scenario, not a customer cohort forecast. Monthly growth is applied before monthly revenue retention, and the revenue churn rate applies to the full grown MRR. The model does not separate new sales, expansion, downgrades, customer counts, or changing rates. The 24 month end MRR gaps are summed using a monthly billing proxy; they are not actual invoices, collected revenue, or recognized revenue. This is different from MRR Runrate’s additive convention. Starting MRR may be zero, in which case all projected MRR remains zero. Inputs must be finite, growth cannot be below −100%, and revenue churn must be between 0% and 100%. Values outside the supported numeric range are unavailable.
Key terms
- Monthly recurring revenue (MRR)
- Monthly recurring revenue is the recurring subscription revenue represented at a month end. This scenario treats each modeled MRR difference as one month of billing for its cumulative proxy.
- Revenue churn
- The percentage of recurring revenue lost during a month. The input is a revenue rate, not a count of customers who cancel.
- Gross MRR path
- The modeled MRR path before applying revenue churn. Each month applies the growth rate first.
Related analysis
Compare this revenue churn scenario with separate lifetime value and acquisition cost tools. They answer different questions and use different inputs.
MRR Runrate uses an additive monthly growth and churn convention. This simulator applies growth first and revenue retention second, so its projection is not directly interchangeable with that tool.
FAQ
How does the model apply growth and churn?
Each month, the model applies the growth rate to MRR first, then applies the revenue retention rate. A constant monthly revenue churn rate therefore compounds across the 24 month scenario.
Is this customer churn or revenue churn?
Revenue churn is the share of recurring revenue lost in a month. It is not a count of customers who cancel. The model applies it to the MRR after monthly growth.
How is the cumulative gap calculated?
For each month, it subtracts modeled net MRR from modeled gross MRR. It then adds that month end MRR gap to the gaps from earlier months.
Is the cumulative gap actual revenue lost?
No. The sum treats each month end MRR gap as a monthly billing proxy. It does not calculate invoices, cash collected, refunds, or recognized revenue.
Does this use the same formula as MRR Runrate?
No. Growth is applied first and revenue retention second, so the net monthly factor is (1 + growth) × (1 − churn). MRR Runrate uses an additive growth minus churn factor and answers a different question.
Related tools
Use a separate MRR run rate calculation when you want an additive growth less churn scenario. Use lifetime value and acquisition cost analysis for customer unit economics.