How Do You Accurately Calculate Year-to-Date Attrition? Seeking Clear Methods and Insights

I want to know the correct method of calculating attrition YTD, i.e., year to date.

Dear Vineet, thank you for the help. I would like to know the formula for Year-to-Date (YTD). For instance, if I wish to calculate the attrition percentage from April to October, what method should I use?

Example Data for Attrition Calculation

Here is an example with the headcount at the end of each month and the number of employees who left the company:

- April: 145 employees, 3 left
- May: 142 employees, 2 left
- June: 142 employees, 5 left
- July: 147 employees, 7 left
- August: 149 employees, 7 left
- September: 150 employees, 2 left
- October: 152 employees, 1 left

How can I calculate the attrition rate from April to October?

How can we forecast the attrition for the coming month or year?