SaaS Churn

Calculating Customer Churn Rate

Churn rate is the percentage of customers who canceled during a period, and it’s simply the number lost divided by the number you started with. Enter how many customers you had at the start of the period and how many you lost, and this calculator returns your churn rate, retention rate, remaining customers, and what that rate compounds to over a full year.

This is distinct from the SaaS Metrics Calculator calculator, which takes a churn rate as an already-known input to compute customer lifetime value — this calculator computes that churn rate itself.

Key Factors to Consider

• This measures pure churn, not net growth. New customers gained during the period aren’t part of this calculation — a business can have real churn happening and still grow overall, as long as new signups outpace losses. Churn and growth are two separate numbers worth tracking together, not one number standing in for overall business health.
• A single blended churn rate can hide big differences between customer segments. Churn often varies meaningfully by signup cohort, plan tier, or acquisition channel — a healthy-looking blended rate can mask one segment with much worse retention than the rest.
• Voluntary and involuntary churn are different problems with different fixes. A customer who actively cancels (voluntary churn) is a different situation than one lost to a failed payment or expired card (involuntary churn) — the second is often recoverable with better payment-retry and dunning processes, a real, actionable lever this single blended rate doesn’t separate out.
• What counts as a “good” churn rate varies a lot by business type. B2B or enterprise SaaS typically sees — and needs — much lower churn than consumer or small-business-focused products, so compare your rate against similar businesses, not a single universal benchmark.

The Formula

$$\vC{\text{Churn Rate}} = \frac{\vB{\text{Customers Lost}}}{\vA{\text{Customers at Start}}} \times 100$$ $$\text{Annualized Churn} = \left(1 - \left(1 - \frac{\vC{\text{Churn Rate}}}{100}\right)^{12}\right) \times 100$$

Worked Example

500 customers at the start of the month, 25 lost during the month:

1. Churn Rate: $\frac{\vB{25}}{\vA{500}} \times 100 = \vC{5\%}$.
2. Retention Rate: $100\% - 5\% = 95\%$, leaving 475 customers.
3. Annualized Churn: $\left(1 - (1 - 0.05)^{12}\right) \times 100 \approx 46\%$ — notably higher than 12 × 5%, since churn compounds against a shrinking base each month.

Common Mistakes

• Simply multiplying the monthly rate by 12 instead of compounding it. As the worked example shows, a 5% monthly churn rate compounds to about 46% annualized, not 60% — multiplying directly overstates the true annual loss.
• Comparing a blended churn rate against a single universal “good” benchmark. What counts as healthy varies enormously by business type — compare against similar businesses (B2B vs. consumer, enterprise vs. small business), not one number everyone quotes.
• Treating churn and growth as the same measurement. A business can have real churn happening every month and still grow overall if new signups outpace the losses — track both numbers together, not one in place of the other.

Useful to Know

• Have a churn rate already and need to compute customer lifetime value or CAC payback? SaaS Metrics Calculator takes churn as an input to compute those downstream metrics.
• Want to see how customer acquisition cost compares against what those customers are worth before they churn? Customer Acquisition Cost (CAC) Calculator computes CAC directly.
• Wondering how churn and revenue together affect when the business turns profitable? Break-Even Point Calculator finds that break-even point.