Measure how many employees leave over a period without being replaced one-for-one.
Please do not make financial decisions based on these results.
What is the Attrition Rate Calculator?
Measure how many employees leave over a period without being replaced one-for-one. To use the Attrition Rate Calculator, enter employees who left, headcount at start, headcount at end; it returns attrition rate, average headcount, and shows them instantly as you type.
Where the Attrition Rate Calculator fits
Measure how many employees leave over a period without being replaced one-for-one. The main figure it returns is the Attrition rate, worked out from the values you enter.
It belongs with the other hr & workforce tools. If you are comparing options or checking a result from another angle, try the Turnover Rate Calculator, Bill Rate Calculator or the DART Rate Calculator.
How to use the Attrition Rate Calculator
- Fill in the fields. You will need Employees who left, Headcount at start, Headcount at end. Use real figures from your own records where you can. Fields marked optional can stay at zero.
- Read the result. The highlighted box gives the Attrition rate, and the cards below show Average headcount. Tables and charts break it down further.
- Test other scenarios. Results update as you type. Change one value at a time to see what drives the answer, and press Reset to go back to the defaults.
Formula and how it works
Example with real numbers
Here is the Attrition Rate Calculator using the default values shown in the calculator above:
Inputs
| Employees who left | 18 |
|---|---|
| Headcount at start | 120 |
| Headcount at end | 110 |
Results
| Attrition rate | 15.65% |
|---|---|
| Average headcount | 115 |
With these inputs the calculator returns Attrition rate: 15.65%. Change any value in the calculator to see how the result moves.
What if you change one input?
Sensitivity check: raising Employees who left from 18 to 21.6 (about 20% higher) and leaving everything else as in the example above changes the results like this:
| Result | Example | After the change | Change |
|---|---|---|---|
| Attrition rate | 15.65% | 18.78% | +20% |
| Average headcount | 115 | 115 | 0% |
The input that moves the result most is the one to check twice. Change it in the calculator above to test your own case.
What the results tell you
The results panel of the Attrition Rate Calculator reports Attrition rate and average headcount. Compare these figures while changing one input at a time, and use the related calculators below to look at the same situation from another angle.
Method and limits. This calculator applies the formula in the section above to your inputs, in your browser; nothing you enter is stored on our servers. The result is only as accurate as the numbers you enter and the formula shown above. It is for information, not financial, tax or legal advice.
Frequently asked questions
How is attrition different from turnover?
Attrition counts leavers whose roles are not refilled; turnover counts all departures.
Which period should I measure over?
Use the same period (month, quarter or year) for every input so the ratios stay comparable.
How do I calculate turnover rate?
Divide the number of leavers by the average headcount for the period and multiply by 100.
Are the results guaranteed?
No. Results depend entirely on the numbers you enter and the formulas shown on this page. Please do not make financial decisions based on them alone; confirm important figures with a licensed professional.
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