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How to Calculate the 12-Month Period for FMLA Leave

4 Methods for Calculating the 12-Month Period for FMLA Leave

No matter how long you've been in HR, you’ve probably at least heard of the Family and Medical Leave Act (FMLA).

As a refresher, here’s what it is: FMLA guarantees eligible employees the ability to take unpaid family or medical leave for up to 12 weeks every 12 months. You can find out more about FMLA from DOL.gov by clicking here.


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The key is in how the employer designates the 12-month period for an FMLA year. FMLA allows employers to choose any one of the following four methods to determine the 12-month period that eligible employees may take up to 12 weeks of qualifying leave. 

An employee’s 12-week FMLA leave can be calculated using the calendar year, any fixed 12-month year, the first day of FMLA leave or a rolling period.

4 ways to determine qualifying FMLA leave. 

  1. The calendar year.

  2. Any fixed 12-month leave year, such as a fiscal year or a year starting on an employee's anniversary date.

  3. The 12-month period measured forward from the date any employee's first FMLA leave begins.

  4. A rolling 12-month period measured backward from the date an employee uses any FMLA leave.

Calendar year or fixed 12-month/anniversary date calculation method.

In either of the first two methods, the employee would be entitled to up to 12 weeks of FMLA leave at any time in the fixed 12-month period.  An employee could potentially take 12 weeks of leave at the end of the year and 12 weeks at the beginning of the following year.

First day of FMLA leave calculation method.

In the third option, an employee would be entitled to 12 weeks of leave during the year beginning on the first date FMLA leave is taken. The next 12-month period would begin the first time FMLA leave is taken after completion of any previous 12-month period. 

As an example, if the employee begins FMLA leave on June 1, 2019, then the next 12-week period would begin again on June 1, 2020.

The rolling 12-month period calculation method.

The last option may be the most complex method you to calculate FMLA periods. Under this method, called the rolling 12-month period, each time an employee takes FMLA leave, the remaining leave entitlement would be any balance of the 12 weeks (which has not been used during the immediately preceding 12 months). Let’s break this down using an example.

If an employee has taken eight weeks of leave during the past 12 months, an additional four weeks of leave could be taken.  If an employee used four weeks beginning Feb. 1, 2019, four weeks beginning June 1, 2019, and four weeks beginning Dec. 1, 2019, the employee would not be entitled to any additional leave until Feb. 1, 2020. However, beginning on Feb. 1, 2020, the employee would again be eligible to take the full 12-week FMLA leave.

If you do use the rolling 12-month period, you may need to calculate whether the employee is entitled to take FMLA leave each time that leave is requested. Employees taking FMLA leave on such a basis may fall in and out of FMLA protection based on their FMLA usage in the prior 12 months.

How to outline and communicate your FMLA policy.

It is recommended that you designate how the FMLA leave will be calculated and ensure that the method is carefully explained in your employee handbook or company policy manual. Once selected, the preferred calculation method should be applied consistently and uniformly to all employees. 

If you need to change to another alternative, it is required that you give at least 60-days’ notice to all employees. If you transition to a new type of period, employees must retain the full benefit of 12 weeks of leave under whichever method affords the greatest benefit to the employee.

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Editor's Note: This post was originally published in June 2012 and has been updated for freshness, accuracy, and comprehensiveness. 

Disclaimer: Please note that this Q&A is not all inclusive. Our guidance is designed only to give general information on the issues actually covered. It is not intended to be a comprehensive summary of all laws which may be applicable to your situation, treat exhaustively the subjects covered, provide legal advice, or render a legal opinion. Consult your own legal advisor regarding specific application of the information to your own plan.