Can I collect Social Security retirement benefits retroactively?

Yes, if you are over full retirement age (FRA) — the age at which you qualify for 100 percent of the benefit calculated from your lifetime earnings. Social Security does not allow what it calls “retroactivity” if you claim benefits before then.

If you are at full retirement age, which varies according to the year you were born, Social Security will pay benefits starting that month. If you apply one to five months after you reach FRA, you can get retroactive benefits in a lump sum for that number of months. If you file six months or more past full retirement age, you can get up to six months in back benefits.

For example, if you claim benefits four months after you reach FRA, you can get payments for those four months. If you wait until a year after you hit full retirement age, you can get six months of retroactive payments, but not a full year.

Retirees who claimed benefits after FRA and then suspended them used to be able to collect retroactive payments for the entire period in which their benefits were on hold, but Congress ended that option in April 2016. There is now no retroactivity for benefits that were suspended.

Keep in mind

Collecting retroactive benefits gets you an immediate lump sum but carries a future cost: You will lose the delayed retirement credits you earned, which will permanently reduce your payment by two-thirds of 1 percent for each back-paid month — or a total of 4 percent for a six-month retroactive payment.