How this calculator works
Attrition counts employees who leave and are not replaced, whether voluntarily or not, against the average number of people employed during the period. Averaging the opening and closing headcount smooths out hiring surges and layoffs. If you want only voluntary resignations, enter that smaller number in the separations field. The same period should cover the headcount figures and the separations.
Formula
Average headcount = (employees at start + employees at end) / 2. Attrition rate = employees who left / average headcount × 100.
Worked example
A company starts the year with 200 employees, ends with 180 and records 30 separations. Average headcount is 190, so attrition is 30 / 190 = 15.79%, or about 15.8 separations per 100 employees.
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Frequently asked questions
How is attrition different from turnover?
In everyday use the two are often the same. Some employers use turnover for all separations including replacements and attrition only for positions that are not refilled. This calculator measures separations against average headcount, so enter the number that matches your definition.
Should I divide by starting headcount instead?
Some reports do, which gives a larger rate when headcount is falling. The average method is more stable and is the one used here. To reproduce a starting-headcount figure, divide the separations by the starting number yourself.
Can attrition exceed 100%?
Yes, in a small or rapidly shrinking workforce, because more people can leave than the average headcount. The percentage stays meaningful but should be read alongside absolute numbers.