Determine if there are 78 or 79 pay periods in 36 months

Thanks for taking a look.

My retirement plan determines what an individual's monthly retirement benefit is based on the pay for the highest 36 months before the retirement date. For most of us that's the last 36 months.

An enterprising co-worker figured out that some 36 consecutive months have 79 pay periods (every two weeks) while most just have 78. This is because we're paid every two weeks and some months have three paydays.

He painstakingly figured out by hand which weeks it would be best to retire in to get an average of 79 paychecks rather than 78. And then he retired! A group of us have been using his chart for a while but it's almost to its end date.

The attached shows how if I retire on November 2022 or January of 2023 my retirement will be based on 78 checks. But if I retire in December of 2022, it will be based on 79 paychecks.