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Attrition Rate Calculator

Table of contents

What is attrition?How to use this attrition calculator?How to calculate attrition?Other tools that might be useful for you

Use our attrition rate calculator if you're curious how your company's annual attrition compares to others. Now, you can quickly check out this metric and find more insights about the company. This HR calculator will show you how to calculate attrition with ease! Explore the rest of the article to learn more.

What is attrition?

Nowadays, companies are all about gaining insights, gathering new information, and learning what is happening on every level. It's no surprise — after all, data is the new oil! You have come to the right place if you want additional insights about your organization to make more informed decisions.

So what is attrition? Attrition is the departure of employees from the company, whether voluntarily or involuntarily, due to any reason like resignation, termination, retirement, or unfortunate circumstances like death. It's a metric used commonly by HR to gain more insights about the company.

Usually, attrition is calculated over a one-year period. However, our calculator is flexible — it allows you to calculate attrition for any time period you prefer. Whether it's a quarter, a month, or even a day, simply input the data from your desired period, and Omni will handle the rest. The annual attrition rate is given in percentage, and it will tell you how well the company is doing in terms of keeping employees and replacing those who left. It will also show you if your company is growing or decreasing in staff size.

How to use this attrition calculator?

First, you need to know the timeframe you want to calculate, and then adjust your employment numbers accordingly. For example, if you want to calculate the annual attrition rate for any given year, you need to enter the following in the attrition rate calculator:

  • Number of employees at the beginning of the year;
  • Number of employees at the end of the year; and
  • Number of employees that left during that period.

⚠️ Please keep in mind that having half or a negative amount of individuals is impossible. Our calculator only accepts non-negative integers as inputs.

How to calculate attrition?

The calculation formula used in this HR calculator is quite simple. You add the number of employees at the beginning of the period to the number at the end, and divide it by 2 to get the arithmetic mean. Then we divide the number of employees that left by the arithmetic mean, and multiply the result by 100 to see the outcome in percentage.

Here's the calculation formula used in our attrition rate calculator:

Attrition=L12(S+E)×100%\small \rm{Attrition} = \frac{L}{\frac12(S+E)} \times 100\%


  • LL — Number of employees that left;
  • SS — Number of employees at the start; and
  • EE — Number of employees at the end.

Other tools that might be useful for you

  • Turnover rate calculator — Now that you know what is attrition and you calculated annual attrition, you might be interested in yet another HR calculator. This one helps you calculate the turnover rate of employees in the organization.
  • Revenue per employee — In addition to that, you might also be interested in our average revenue calculator, which will give you a quick insight into salaries.
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