How to Calculate Churn Rate: Every Formula SaaS Founders Need
Customer churn, revenue churn, net churn, annualized churn. There are multiple ways to calculate churn and each tells a different story. Here is every formula you need with real examples.
Customer churn rate = (customers lost / customers at start of period) x 100. Revenue churn rate = (MRR lost / MRR at start of period) x 100. Net revenue churn subtracts expansion revenue. A 5% monthly churn compounds to 46% annual churn. Always use start of period count, never end of period, to avoid understating churn.
The Four Churn Formulas Every Founder Needs
Churn rate sounds simple but there are multiple ways to calculate it, and each version tells you something different about your business. Using the wrong formula leads to bad decisions.
Here are the four formulas that matter, with real numbers.
1. Customer Churn Rate (Logo Churn)
Formula:
Customer Churn Rate = (Customers Lost During Period / Customers at Start of Period) x 100
Example:
Start of March: 200 customers. During March: 10 customers cancel.
Customer Churn = (10 / 200) x 100 = 5%
This tells you what percentage of your customer base is leaving. It does not tell you how much revenue you lost, because not all customers pay the same amount.
When to use it: Tracking product market fit. If logo churn is high, customers are not finding enough value regardless of what they pay.
Use the [churn rate calculator](/churn-rate-calculator) to run these numbers for your own SaaS.
2. Revenue Churn Rate (Gross MRR Churn)
Formula:
Revenue Churn Rate = (MRR Lost to Cancellations + MRR Lost to Downgrades) / MRR at Start of Period x 100
Example:
Start of March MRR: $20,000. Cancellations: $800. Downgrades: $200.
Revenue Churn = ($800 + $200) / $20,000 x 100 = 5%
Revenue churn can differ significantly from customer churn. If your two highest paying customers ($500/mo each) cancel while 20 customers on your $19 plan stay, logo churn is low but revenue churn is devastating.
When to use it: Understanding actual financial impact. This is the number that matters for runway and growth projections. Calculate the dollar impact with the [true cost of churn calculator](/churn-cost-calculator).
3. Net Revenue Churn
Formula:
Net Revenue Churn = (MRR Lost minus MRR Gained from Expansion) / MRR at Start of Period x 100
Example:
Lost MRR: $1,000. Expansion MRR (upgrades, add ons): $600.
Net Revenue Churn = ($1,000 minus $600) / $20,000 x 100 = 2%
Net revenue churn is the most optimistic view of churn because it credits expansion revenue. If expansion exceeds losses, net churn goes negative, meaning your existing customers are growing your revenue even without new signups.
When to use it: Investor conversations and long term planning. Negative net churn is the gold standard for SaaS. But do not let it mask a high gross churn problem. If you are losing 8% of customers but upselling the rest to compensate, you still have a retention problem.
4. Annualized Churn
Formula:
Annual Churn = 1 minus (1 minus Monthly Churn Rate) ^ 12
Example:
Monthly churn: 5%
Annual Churn = 1 minus (1 minus 0.05) ^ 12 = 1 minus 0.54 = 46%
Critical mistake to avoid: Do NOT multiply monthly churn by 12. A 5% monthly rate is not 60% annual. It is 46% because churn compounds, each month you lose 5% of the remaining base, not the original base.
| Monthly Churn | Wrong (x12) | Correct (compounded) |
|---|---|---|
| 2% | 24% | 21.5% |
| 5% | 60% | 46.0% |
| 7% | 84% | 58.0% |
| 10% | 120% | 71.8% |
The difference between the wrong calculation and the correct one grows dramatically at higher churn rates. At 10% monthly, the naive calculation gives you 120% (impossible) while the real number is 72%.
Common Calculation Mistakes
Mistake 1: Using end of period count
If you divide customers lost by customers at end of month (which already excludes the churned ones), you understate churn. Always use the count at the start of the period.
Wrong: 10 lost / 190 remaining = 5.3%
Right: 10 lost / 200 starting = 5.0%
Mistake 2: Including new customers in the denominator
If you add 30 new customers during the month and use 230 as your denominator, you dilute the churn rate artificially. Churn rate should only measure what happened to the cohort that existed at the start of the period.
Mistake 3: Not separating voluntary and involuntary churn
If your churn rate is 6%, knowing that 2.5% is involuntary (failed payments) and 3.5% is voluntary (active cancellations) completely changes your strategy. Involuntary churn has a straightforward fix: [dunning emails](/blog/reduce-involuntary-churn-failed-payment-recovery). Voluntary churn requires product and retention work.
Mistake 4: Ignoring downgrades
A customer who drops from $99/mo to $19/mo did not cancel, so they do not show up in logo churn. But you lost $80/mo in revenue. Revenue churn catches this. Logo churn does not.
Which Churn Formula Should You Use?
For daily decisions: Gross revenue churn. It shows the real financial bleeding without any optimistic offsets.
For investor updates: Net revenue churn. Investors want to see that your existing customer base is healthy and expanding.
For product priorities: Customer (logo) churn by cohort. If new cohorts churn faster than old ones, your product is getting worse for new users. If old cohorts suddenly spike, something changed (pricing, competition, feature removal).
For growth modeling: Annualized churn (compounded). Use it to project MRR 12 months out and calculate how much new revenue you need to hit targets.
Churn Rate in Practice: A Real Example
SaaS at $15K MRR, 300 customers.
| Metric | Count | Amount |
|---|---|---|
| Cancellations | 12 | $720 |
| Downgrades | 3 | $150 |
| Failed payments (involuntary) | 8 | $480 |
| Expansions | 5 | $300 |
Customer churn: (12 + 8) / 300 = 6.7% (if failed payments led to full churn)
Gross revenue churn: ($720 + $150 + $480) / $15,000 = 9%
Net revenue churn: ($1,350 minus $300) / $15,000 = 7%
Annualized gross churn: 1 minus (0.91)^12 = 67%
This founder has a serious problem. 9% gross revenue churn means two thirds of their revenue base turns over annually. But the breakdown reveals that $480 (36% of lost MRR) is from failed payments. That is recoverable.
If dunning emails recover 40% of those failed payments, they save $192/mo and drop gross churn from 9% to 7.7%. Over a year, that is $2,304 in saved revenue from just adding payment recovery. See the [ROI of dunning software](/blog/roi-of-dunning-management-software) for the full math.
Start With Your Numbers
Run the free [Revenue Scan](https://app.savemrr.co) to get your exact churn breakdown: voluntary vs involuntary, failed payments, cancellations, downgrades, and recoverable revenue. It takes 60 seconds and needs only a restricted Stripe API key.
Sources: ProfitWell retention benchmarks (2024), Recurly State of Subscriptions (2025), Baremetrics Open Benchmarks, Stripe billing documentation.
Frequently asked questions
What is the formula for churn rate?
Customer churn rate = (customers lost during period / customers at start of period) x 100. For revenue churn, replace customers with MRR amounts. Example: 10 customers lost from 200 starting = 5% monthly churn.
How do I calculate annual churn from monthly churn?
Annual churn = 1 minus (1 minus monthly churn rate)^12. A 5% monthly rate is NOT 60% annual. It is 46% because of compounding. Each month you lose 5% of the remaining base, not the original.
What is net revenue churn?
Net revenue churn = (MRR lost from cancellations and downgrades minus MRR gained from expansions and upgrades) / starting MRR. If expansion exceeds churn, net churn is negative, meaning your existing customers are growing your revenue.
Should I track customer churn or revenue churn?
Track both, but prioritize revenue churn for business decisions. You could have low customer churn but high revenue churn if your biggest customers leave. Revenue churn directly impacts your financial health.
Why does my churn rate look different depending on how I calculate it?
Common causes: using end of period count instead of start (understates churn), including new customers in the denominator (dilutes churn), or mixing voluntary and involuntary churn. Always use start of period count and separate churn types.
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