Short answer: in SaaS, churn rate and attrition rate are used interchangeably. Both mean the percentage of customers (or revenue) lost during a period.
But the terms have different histories in different industries, and occasionally that creates confusion when a finance person and a SaaS person are in the same conversation. Here's what each one means in context.
In SaaS: they're the same metric
SaaS adopted "churn rate" as the standard term, but "attrition rate" is sometimes used in the same way, especially in board decks and financial reports. The formula is identical:
Churn Rate (or Attrition Rate) = (Customers Lost During Period / Customers at Start) x 100
Most SaaS teams default to "churn." Use "attrition" when your audience is from finance, insurance, or HR backgrounds where that term is more native.
In HR and recruiting: attrition is more specific
In HR, attrition specifically means voluntary departure - employees who chose to leave. It's distinct from "turnover," which includes both voluntary and involuntary (layoffs, firings) departures.
This usage doesn't usually leak into SaaS reporting, but if you're discussing employee retention with HR, the distinction matters.
In insurance and banking: attrition is policy-specific
Insurance uses "attrition" to describe policy non-renewals at the end of a term. "Churn" in those industries can include canceled policies mid-term or other forms of customer loss. Slightly different definitions but the math ends up similar.
Which one to use in your reports
For SaaS metrics work:
- Internal team conversations: "churn" - shorter, industry-standard.
- Board reports: "churn" if your board is SaaS-native, "attrition" if they're from finance.
- Investor calls: Match the term your investors use. Most use "churn" these days.
- Customer-facing content: "Churn" is now common enough that customers understand it.
The thing you should actually focus on
Whichever term you use, what matters is breaking the metric into components:
- Voluntary vs involuntary churn (see voluntary churn)
- Logo churn vs revenue churn (customer count vs MRR lost)
- Gross churn vs net churn (with vs without expansion)
- Cohort retention (more useful than blended averages)
The terminology is much less important than the breakdown. See how to calculate churn rate correctly for the full framework.
Want to know if your churn (or attrition) is healthy?
Take the 60-second Churn Health Check. It scores your retention setup and tells you whether your numbers are healthy for your segment.