100%.

That’s the turnover rate you can have even if headcount doesn’t shrink. Since turnover is often used to measure retention, it can be misleading.

What’s the difference between attrition and turnover?

Attrition is the departure rate. Calculation:

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Turnover is the renewal rate. Calculation:

Why track one over the other?

Attrition measures departures only—number of leavers over average headcount for a period. If you’re in a startup, attrition is the indicator to track for retention.

To go deeper on retention, break attrition down: probation‑period attrition, attrition by gender, etc. See: “How to respond to departures in your company.”

Turnover measures renewal—how much your workforce changed over a period, counting both joins and exits.

In a high‑growth startup, hiring is fast, so renewal is high. Your turnover rate will be high—and potentially misleading.

Example: you grow from 0 to 100 people (only hiring). Turnover is 100%.

Industry note: Turnover is commonly used in hospitality and retail and can reach 70%.

Which period should you use?

Rates vary with the time window. Longer periods include more departures.

Example:

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Attrition over 1 year

• Jan 1: 100 employees
• Dec 31: 500 employees
• 120 departures during the year
• Result: 40% attrition

Attrition over half a year

• Oct 1: 450 employees
• Dec 31: 500 employees
• 30 departures during the half year
• Result: 6% attrition

When comparing attrition (or turnover), always use the same time period.