# Attrition Rate Calculator

URL: https://speedycalculator.com/calculators/finance/attrition-rate/
Last updated: 2026-10-25

> The attrition rate calculator works out the percentage of employees who left an organisation in a period, from headcount at the start and end and the number who left, and annualises a monthly or quarterly rate.

## Inputs

- Employees at the start
- Employees at the end
- Employees who left
- Period

## Results

- Average headcount
- Attrition rate for the period
- Annualised attrition rate
- Retention for the period

## Formula

```
Attrition rate = employees who left ÷ average headcount × 100
Average headcount = (start + end) ÷ 2
Annualised rate = 1 − (1 − period rate)^(periods per year)
```

## Explanation

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

FieldWhat to enterEmployees at the startA numberEmployees at the endA numberEmployees who leftA numberPeriodChoose 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 startAttrition rate for the period (%)609.68908.331207.321506.521805.882404.92

## 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 %.

## FAQ

**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.


## Sources

- [SHRM – Turnover and retention](https://www.shrm.org/)