Attrition Rate Calculator

Calculate employee attrition rate using departures and average headcount.

Calculate workforce attrition

Enter opening headcount, closing headcount and departures for the same reporting period.

Opening headcount

Closing headcount

Employee departures

Average headcount—

Attrition rate—

Approx. non-departure share—

How the calculation works

Attrition rate = employee departures ÷ average headcount × 100, where average headcount is (opening headcount + closing headcount) ÷ 2. This is a common period-level approximation when daily or monthly average headcount is not available.

How to use the result

Use the metric to compare teams or periods only when departure definitions are consistent. You may also separate voluntary and involuntary departures to understand what is driving the headline rate.

Assumptions and limitations

Different organizations use different denominators and may annualize rates. This calculator does not annualize automatically and does not distinguish resignation, termination, retirement or internal transfer unless you choose which departures to include.

Example

If opening headcount is 100, closing is 95 and there are 12 departures, average headcount is 97.5 and period attrition is about 12.31%.

Frequently asked questions

Should I include involuntary departures?

That depends on your reporting definition. Use a consistent inclusion policy and consider reporting voluntary attrition separately.

Does the tool annualize monthly attrition?

No. It reports the rate for the data period you enter.

Why use average headcount?

Average headcount better represents the workforce exposed to attrition during the period than using only the opening or closing count.

Can I compare departments?

Yes, if each department uses the same time period and departure/headcount definitions.