How do you calculate attrition rate?

Divide the number of people who left during the period by the average headcount over that period, then multiply by 100. The average headcount is usually the starting number plus the ending number, divided by two. For example, 18 leavers against an average of 205 staff is an attrition rate of about 8.78%.

What is the difference between attrition rate and turnover rate?

The two terms are often used interchangeably and share the same formula. Some organisations use attrition for roles that are not backfilled and turnover for all departures, but both express leavers as a percentage of average headcount over a period, usually a year.

What is a good attrition rate?

It varies widely by industry. Many employers aim for an annual attrition rate below 10%, but hospitality and retail often run much higher while established professional firms run lower. Compare your rate against others in your sector rather than a single benchmark.

Attrition Rate Calculator

This attrition rate calculator turns three simple numbers, the people who left, your headcount at the start and your headcount at the end, into the attrition rate and retention rate for the period. Attrition rate, also called staff turnover, measures how many employees leave relative to the size of your team, and it is one of the most watched numbers in any people or HR dashboard. High attrition is expensive: every departure means recruiting, onboarding and lost knowledge, so tracking the rate over time tells you whether retention is improving or slipping. The standard method divides leavers by the average headcount over the period, where the average is the starting number plus the ending number divided by two, then multiplies by 100 to get a percentage. Using the average rather than the starting figure keeps the rate fair when a team is growing or shrinking. Enter your figures for a month, a quarter or a full year, and the calculator also shows the retention rate, which is simply the share of staff who stayed. Compare the result against others in your industry, since a healthy rate for hospitality or retail looks very different from one for a professional firm. It works equally well for a whole organisation, a single department or one team.

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Employees who left

Headcount at start

Headcount at end

Use figures for the same period, a month, quarter or year. The average headcount is the start plus end, divided by two.

8.78%

attrition rate for the period

Average headcount205

Employees who left18

Retention rate91.22%

Losing 18 people against an average headcount of 205 is an attrition rate of 8.78% for the period, so you retained 91.22% of staff.

How it works

The attrition rate is leavers divided by average headcount, times 100. The average headcount is the starting headcount plus the ending headcount, divided by two, which smooths out growth or shrinkage over the period. Written out, attrition rate = leavers / ((start + end) / 2) x 100. The retention rate is the mirror image, 100 minus the attrition rate, showing the percentage of the team that stayed. Keep your leaver count and your headcounts to the same period so the percentage is meaningful, and annualise short periods only with care, since a busy month does not always scale to a full year.

Worked example

Say 18 people left over the year. You started with 200 staff and finished with 210, so the average headcount is (200 + 210) / 2 = 205. The attrition rate is 18 / 205 x 100 = 8.78%, which means about one in eleven staff left over the year. The retention rate is 100 - 8.78 = 91.22%, so just over nine in ten stayed. If instead you had used only the starting headcount of 200, the rate would read 9.00%, slightly overstated because the team grew during the year, which is why the average is the fairer denominator.

Related calculators

Customer Churn Calculator: customer loss rate.
Revenue Per Employee Calculator: output per head.
True Cost of Employee Calculator: full cost of a hire.
Employee Cost Calculator: salary plus on-costs.
Absence Percentage Calculator: absenteeism rate.

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