Attrition Rate Calculator
An attrition rate calculator measures how many employees leave over a period. Enter the headcount at the start and end of the period and the number of people who left to get your attrition rate, retention rate and average headcount.
At a glance
How the attrition rate calculator works
- 1 Enter the number of employees at the start of the period.
- 2 Enter the number at the end of the period.
- 3 Enter how many employees left during the period.
- 4 The calculator uses average headcount to give an accurate attrition and retention rate.
Average headcount = (Start + End) ÷ 2. Attrition rate % = Leavers ÷ Average headcount × 100. Retention rate % = 100 − Attrition rate.
Worked example
A company starts the year with 320 employees and ends with 295. Forty-two people left during the year.
- ·Employees at start: 320
- ·Employees at end: 295
- ·Employees who left: 42
- 1. Average headcount = (320 + 295) ÷ 2 = 307.5
- 2. Attrition rate = 42 ÷ 307.5 × 100 = 13.66%
- 3. Retention rate = 100 − 13.66 = 86.34%
- 4. Employees retained = 307.5 − 42 = 265.5
Attrition 13.66%, retention 86.34%, against an average headcount of 307.5.
Using average headcount rather than the opening 320 matters here: on the starting figure the rate would read 13.13%, and on the closing figure 14.24%. The average is the standard denominator precisely because it does not flatter a shrinking company or penalise a growing one. Also note the company shrank by 25 while losing 42 — so 17 people were hired, and a headline attrition figure alone would not have told you that.
Frequently asked questions
How do you calculate attrition rate?
Divide the number of employees who left during the period by the average headcount, then multiply by 100. Average headcount is the starting count plus ending count divided by two — this avoids distortion when the company is growing or shrinking.
What is the difference between attrition and turnover?
They are often used interchangeably. Strictly, turnover counts all departures (including backfilled roles), while attrition sometimes refers to roles left unfilled. Both are measured as departures ÷ average headcount × 100.
What is a healthy attrition rate?
Around 10% or below per year is generally considered healthy, though it varies by industry. Rates above 20% usually warrant investigation into pay, management, workload or career growth.
Why use average headcount instead of starting headcount?
Using the average smooths out growth or contraction during the period, so a company that doubled in size is not credited with an artificially low rate. It is the standard denominator in HR analytics.
How do you calculate attrition rate?
Divide the number of employees who left during the period by the average headcount for that period, then multiply by 100. Average headcount is the opening count plus the closing count divided by two. Using average headcount rather than the starting figure is what keeps the rate honest when the company is growing or shrinking during the period.
What is the difference between attrition and turnover?
They are used interchangeably in most reporting, and both are calculated the same way. Where a distinction is drawn, turnover counts every departure including those backfilled, while attrition sometimes refers specifically to roles left unfilled — a shrinking of the workforce. What matters more than the label is that you state which departures are included, because that is what makes the figure comparable across periods.
What is a healthy attrition rate?
It depends heavily on sector and role mix, so treat any single benchmark with suspicion. Around 10% a year or below is generally considered comfortable for professional roles; retail, hospitality and contact centres routinely run much higher as a normal feature of the work. The more useful question is your own trend, and whether the rate among your strongest performers differs from the average.
Should I separate voluntary from involuntary exits?
Yes — they mean opposite things. Voluntary departures point at pay, management, workload or career path. Involuntary ones reflect hiring quality and performance management. A 14% rate that is mostly involuntary is a recruitment problem; the same 14% mostly voluntary is a retention problem, and the interventions are completely different. Report them as separate lines.
How often should attrition be measured?
Monthly for early warning, annualised for reporting and comparison. Beware annualising a single month with small numbers: three departures in a 100-person month is 36% annualised, which is noise rather than signal. Use a rolling twelve-month figure for trend and the monthly count for spotting a change worth investigating.