Most employers use the calendar method to calculate the 12-month leave year period for employees taking leave under the federal Family and Medical Leave Act (FMLA).

Over four weeks, we asked subscribers which method they use to calculate the 12-month leave period during which employees may take FMLA leave. The votes stacked up as follows:

• Calendar year: 50 percent
• Measured forward: 22 percent
• Rolling backward: 17 percent
• Another static 12-month period: 11 percent

While the calendar year method is the easiest method to use, it does allow for stacking of leave. If, for example, an employee began taking FMLA leave on November 1, the employee could take all of November and all of December, and get another 12 weeks of FMLA leave on January 1.

Using this method, therefore, can result in the employee taking up to 24 continuous weeks of FMLA leave, 12 weeks falling in on 12-month leave year period, and the other 12 falling in the next 12-month leave year period.

Measured forward came in second, which can be a bit more challenging as each situation has its own leave year, and employees can also stack the leave similar to the calendar year method.

The rolling backward method came in third at 17 percent. This method can be the most challenging to use, but it avoids the stacking of leave. Each time an employee takes FMLA leave, employers are to look back and see how much leave the employee took in the previous 12 months. That amount is then subtracted from the employee’s 12-week FMLA leave entitlement.

Using another static 12-month leave year (e.g., fiscal year, employee anniversary) came in last at 11 percent. This has similar challenges as the measured forward method.

Key to remember: While employers generally have a choice of which method to use to calculate the 12-month leave year period, the method should be chosen carefully, considering the challenges each method brings.