Attrition Rate Calculator
Calculate your organization's employee attrition (turnover) rate over any period to benchmark workforce stability.
How to use this tool
- Enter employees at start of period, employees at end of period and number of employees who left in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your attrition rate and the full breakdown beneath it.
⚠ This tool provides general estimates for education only and is not financial, tax or legal advice. Figures may not reflect your situation — verify with a qualified professional.
Formula
Average Employees = (Employees at Start + Employees at End) / 2
Attrition Rate = (Number Who Left / Average Employees) × 100%
Retention Rate = 100% − Attrition Rate
How it works
The attrition rate (also called the employee turnover rate) measures the percentage of an organization's workforce that leaves during a given period. The average of the headcount at the start and end of the period is used as the denominator to account for workforce fluctuations.
This calculator uses the standard SHRM methodology of dividing separations by the average headcount. The result can be annualized by multiplying a monthly or quarterly rate by 12 or 4, respectively.
Worked example
Annual Attrition for a 100-Person Team
- Start of year: 100 employees. End of year: 90 employees. Employees who left during the year: 15.
- Average employees = (100 + 90) / 2 = 95.
- Attrition rate = (15 / 95) × 100 = 15.789%, rounded to 15.79%.
- Retention rate = 100% − 15.79% = 84.21%.
The annual attrition rate is 15.79%, with a retention rate of 84.21%.
Common mistakes to avoid
- Dividing departures by the starting headcount only instead of the average of start and end headcount, skewing the rate during periods of rapid hiring.
- Lumping voluntary resignations and involuntary terminations together — the two have different causes and should ideally be tracked separately.
- Annualizing a monthly rate by multiplying by 12 without accounting for compounding, which overstates true annual attrition.
Key terms
- Attrition Rate
- The percentage of employees who leave an organization (voluntarily or involuntarily) over a specific period, relative to the average workforce size.
- Retention Rate
- The percentage of employees who remain with an organization during a given period; equal to 100% minus the attrition rate.
- Average Headcount
- The mean number of employees during a period, calculated as the average of the opening and closing headcounts.
- Voluntary vs. Involuntary Attrition
- Voluntary attrition occurs when employees choose to leave; involuntary attrition results from dismissals, layoffs, or retirement.
Frequently asked questions
- What is a healthy employee attrition rate?
- It depends heavily on industry. Retail and hospitality often see 40-60% annually; professional services typically aim for under 15%. Compare your rate to sector benchmarks, not a universal number.
- How do I calculate attrition for a single month?
- Divide departures in that month by average employees for that month (start + end headcount / 2), then multiply by 100. Multiply by 12 for an annualized estimate.
- Is attrition rate the same as turnover rate?
- Often used interchangeably, but some HR professionals distinguish them: attrition refers to positions not refilled, while turnover includes replacement hiring. This calculator measures total departures.