(According to the Social Security Administration)
There are a couple of circumstances where the Social Security Administration changes your birthdate for you. Chances are if this applies to you, you already know this, but I thought I’d explain it anyhow just so you’ll know what it’s all about.
First of the Month
If your date of birth is on the first day of the month, then for Social Security purposes, your Birth Month is actually the month prior to your actual date of birth. So if you were born on July 1, according to the Social Security Administration, your Birth Month, and therefore the month that your benefit is based upon (for example, Full Retirement Age), is June. In this example, your Birth Year remains the same, but that’s not always the case…
First of January
In the case of a date of birth being January 1, your Birth Month is December, and your Birth Year is the year prior to your actual birth.
Twenty-ninth of February
If you are one of the lucky ones that happen to have been born on Leap Day, February 29 – you’re in luck! The Social Security Administration doesn’t really care what day of the month you were born, only the month and year. So even though your actual date of birth anniversary doesn’t come every year, the month does, and the Social Security Administration counts February as your Birth Month in your case.