Attrition counts every departure – resignations, retirements and dismissals. Some HR teams separate voluntary attrition (resignations) because it is more controllable. Rates vary widely by industry: 10–15% a year is common in offices, much higher in retail and hospitality.
How to use the Attrition Rate Calculator
- Employees at the start
- Employees at the end
- Employees who left
- Period
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter headcount at the start and end of the period, the number of employees who left, and the length of the period.
Tips
- Use figures for the same period (a month, a quarter or a year) for every input so ratios compare like with like.
- Track the metric over time – the trend usually tells you more than a single value.
- Compare your result with industry benchmarks, which vary a lot between sectors.
- Treat the result as a starting point for a decision, then check the assumptions behind each input.
Common mistakes to avoid
- Mixing monthly and yearly numbers in the same calculation.
- Using revenue where the formula needs profit (or the other way round).
- Forgetting hidden costs such as taxes, fees, overheads or your own time.
Inputs explained
| Field | What to enter |
|---|---|
| Employees at the start | A number |
| Employees at the end | A number |
| Employees who left | A number |
| Period | Choose one: Year, Half year, Quarter, Month |
What each result means
- Average headcount = ([Employees at the start] + [Employees at the end])÷2
- Attrition rate for the period = [Employees who left]÷[Average headcount]×100
- Annualised attrition rate = (1 – (1 – [Attrition rate for the period]÷100)^[Period])×100
- Retention for the period = 100 – [Attrition rate for the period]
Example values
How the main result changes when Employees at the start changes and everything else stays at the example values above:
| Employees at the start | Attrition rate for the period (%) |
|---|---|
| 60 | 9.68 |
| 90 | 8.33 |
| 120 | 7.32 |
| 150 | 6.52 |
| 180 | 5.88 |
| 240 | 4.92 |
Formula
Attrition rate = employees who left ÷ average headcount × 100Average headcount = (start + end) ÷ 2Annualised rate = 1 − (1 − period rate)^(periods per year)Worked example
Inputs — Employees at the start: 120; Employees at the end: 126; Employees who left: 9; Period: Quarter.
Results — Average headcount = 123; Attrition rate for the period = 7.32 %; Annualised attrition rate = 26.21 %; Retention for the period = 92.68 %.
Frequently asked questions
What is a healthy attrition rate?
Around 10% a year is often considered healthy; it depends on the industry.
Is attrition the same as turnover?
They are often used interchangeably; some use attrition for roles left unfilled.
Should I include retirements?
Yes, total attrition includes them; report voluntary attrition separately if useful.
What formula does the Attrition Rate Calculator use?
Attrition rate = employees who left ÷ average headcount × 100.