Confused About the Attrition Rate Formula? Let's Review It Together

I generate MIS reports in which we need to include the attrition formula, but I am a bit confused about it.

Attrition Rate Formula

Attrition Rate = ((No. of Exits × 100) / (Opening Balance + No. of New Joinings))

Kindly review it and let me know if it is correct or incorrect.

Please keep in mind that while calculating attrition, we have to take into consideration only employees who have left the organization on their own. Employees who are desired separations or who were asked to quit the organization should not be considered in your attrition rate.

Attrition Rate Formula

Hence, the formula can be as mentioned below:
Attrition Rate = (Total number of employees left on their own / (Opening balance of manpower at the start of the period + new additions during the period + transfers in the division/department)) * 100

Attrition Rate Formula

Attrition Rate: Total number of employees who left / Opening balance * 100

Regards,
Balaji