What is Churn Rate? (Definition + SaaS example)
Churn rate is the percentage of customers or revenue lost over a given period. In SaaS, churn rate is the inverse of retention — a 5% monthly customer churn means the company loses 5% of its customer base each month. Reducing churn is the single most effective lever for improving LTV, NRR, and long-term revenue growth.
Formula and Calculation
Customer Churn Rate
Customer Churn Rate = (Customers Lost ÷ Customers at Start of Period) × 100
Revenue Churn Rate (Gross)
Gross Revenue Churn = (Churned MRR + Contraction MRR) ÷ Starting MRR × 100
Net Revenue Churn
Net Revenue Churn = (Churned MRR + Contraction MRR − Expansion MRR) ÷ Starting MRR × 100
When net revenue churn is negative, the company has achieved negative churn — the holy grail of SaaS retention.
Worked SaaS Example
A SaaS company starts March with 400 customers and $200,000 MRR:
| Event | Customers | MRR Impact |
|---|---|---|
| Starting base (Mar 1) | 400 | $200,000 |
| Cancellations | −12 | −$4,800 |
| Downgrades | −0 (still active) | −$1,200 |
| Upgrades | +0 (existing) | +$3,500 |
| End of March (existing only) | 388 | $197,500 |
| Churn Metric | Calculation | Result |
|---|---|---|
| Customer churn rate | 12 ÷ 400 | 3.0% |
| Gross revenue churn | ($4,800 + $1,200) ÷ $200,000 | 3.0% |
| Net revenue churn | ($4,800 + $1,200 − $3,500) ÷ $200,000 | 1.25% |
Churn Impact Over 12 Months
Starting with 1,000 customers, different monthly churn rates compound dramatically:
| Monthly Churn | Customers After 12 Months | % Retained |
|---|---|---|
| 1% | 886 | 88.6% |
| 3% | 694 | 69.4% |
| 5% | 540 | 54.0% |
| 10% | 282 | 28.2% |
At 10% monthly churn, the company must replace 72% of its customer base every year just to stay flat.
Logo Churn vs Revenue Churn
Why Churn Rate Matters for SaaS
Finance teams monitor churn because it is the primary leakage in the revenue engine. Every percentage point of monthly churn compounds into significant annual revenue loss. A company with $10M ARR and 5% monthly revenue churn is losing $6M annually from existing customers — requiring massive new sales just to stay flat.
In investor reporting, churn rate is the first retention metric scrutinized. Low churn signals product stickiness, customer satisfaction, and pricing power. Investors model future revenue using churn assumptions, so a small difference in reported churn can meaningfully change projected valuations.
A common mistake is reporting only gross customer churn without breaking it into voluntary and involuntary components. Involuntary churn from failed payments can represent 20–40% of total churn and is largely fixable through dunning automation. Fixing involuntary churn is often the fastest path to improving retention metrics.
Churn rate is the denominator in the LTV formula, making it the most powerful lever in SaaS unit economics. It feeds directly into NRR and GRR calculations and determines whether the company achieves net dollar retention above 100%.
Track and reduce churn with JustPaid
Frequently Asked Questions
Customer churn (logo churn) counts the percentage of customers who cancel. Revenue churn counts the percentage of MRR lost from cancellations and downgrades. A company can have 5% customer churn but only 2% revenue churn if the churned customers were on smaller plans. Revenue churn is generally more important for financial planning.
Related Terms
MRR (Monthly Recurring Revenue)
Monthly Recurring Revenue (MRR) is the predictable revenue a SaaS company earns each month from active subscriptions. MRR normalizes different billing periods — annual, quarterly, and monthly — into one consistent monthly figure, making it the foundational metric for SaaS financial planning.
Revenue Churn
Revenue churn measures how much recurring revenue a SaaS company loses from downgrades and cancellations during a period. It is often expressed as lost MRR or ARR, or as a percentage of starting recurring revenue, and is more financially meaningful than customer churn alone.
NRR (Net Revenue Retention)
Net Revenue Retention (NRR) measures the percentage of recurring revenue retained from existing customers over a period, including expansion, contraction, and churn. An NRR above 100% means a SaaS company is growing revenue from its existing customer base without acquiring a single new customer.
GRR (Gross Revenue Retention)
Gross Revenue Retention (GRR) measures the percentage of recurring revenue retained from existing customers over a period, excluding any expansion revenue. GRR can never exceed 100% and reflects the core stickiness of a SaaS product — how much revenue stays without upsells compensating for losses.
Net Dollar Retention (NDR)
Net Dollar Retention (NDR) measures the percentage change in revenue from existing customers over a period, accounting for expansion, contraction, and churn. NDR above 100% indicates that revenue growth from upsells and cross-sells exceeds revenue lost from downgrades and cancellations — the clearest signal of a sticky, expanding product.
