MRR churn and ARR churn measure the same thing on different time scales. The confusion comes from people assuming the conversion is linear. It isn't.
If your monthly churn is 5%, your annual churn isn't 60%. It's 46%. The math compounds.
The formulas
MRR Churn Rate = (MRR lost during the month / MRR at start of month) x 100
ARR Churn Rate = (ARR lost during the year / ARR at start of year) x 100
The relationship between them:
Annual Churn = 1 - (1 - Monthly Churn)^12
Quick conversion table:
| Monthly Churn | Annual Churn |
|---|---|
| 1% | 11.4% |
| 2% | 21.5% |
| 3% | 30.6% |
| 5% | 46.0% |
| 7% | 58.2% |
| 10% | 71.8% |
When to use each
Use MRR churn for:
- Weekly and monthly team standups (it surfaces problems fast)
- Tracking the impact of new retention experiments
- Diagnosing what's happening right now
Use ARR churn for:
- Board reports and investor updates
- Long-term forecasting
- LTV calculations
- Benchmarking against industry standards (most public benchmarks are annual)
Most SaaS teams should track both. They serve different decisions.
The annual subscriber trap
One reporting pitfall: an annual subscriber who plans to cancel doesn't show up in MRR churn until their contract ends. They've already mentally churned, but the metric won't catch it for months.
The fix is to track contract churn separately from MRR churn. Contract churn flags customers who've notified you of non-renewal even if their billing hasn't ended yet. This gives you 60-180 days of warning instead of finding out at the renewal date.
For the bigger picture, use Net Revenue Retention. It captures both billing models and includes expansion. See the NRR guide.
What you should report (TL;DR)
For most SaaS companies:
- Monthly: Gross MRR churn, Net MRR churn, NRR
- Quarterly: Gross ARR churn, Net ARR churn, cohort retention curves
- Always: Voluntary vs involuntary split (see voluntary churn and involuntary churn guides)
For deeper measurement work, see how to calculate churn rate correctly.
Score your churn measurement setup
Take the 60-second Churn Health Check. It scores your measurement maturity (including whether you track MRR + ARR + NRR correctly) and tells you what to fix first.