The law for people born on leap days

[Chronos]

@SanVito

I imagine it would be 1 March, as the 28th would mean an incomplete year.

But a person born on 1 March would also turn 21 on 1 March. So either the leap baby got a more than complete year in there somewhere, or the March baby got an incomplete year.

Of course, the real answer (which the law, of course, ignores because it’s inconvenient) is that the anniversary of your birth falls on an integer multiple of 365.2425 days after the moment of your birth, which might be on different dates in different years, even for a person born far from Leap Day.

And yes, every year, I do calculate what date (and what time on that date) my birthday will fall on that year.

[Alessan]

@Hari_Seldon

I wonder what countries based on lunar calendars. I think I know what happens in Israel where they use a lunar calendar and add a leap month approximately every third year (actually 7 in every 19 year cycle). The way it was explained to me (@Alessan please correct if I get it wrong) is that in a leap year a second month of Adar (called Adar 2) is added after the standard Adar (now called Adar 1). This has the following consequence. If two friends were born, A on the 29th of Adar 1 and B on the 1st of Adar 2, then although they are only one day apart in age, in any ordinary year, B will celebrate his birthday on the 1st of Adar and A on the 29th. Of course in a leap year A will celebrate his birthday one day before B.

I can’t tell you about the birthdays - only the very religious use the Hebrew calendar for those, so I don’t know the rules - but one thing I do know about Adar Aleph and Adar Bet (as they’re called) is that all Adar holidays and commemorations are held in the second Adar, not the first. In other words, two Adars means one extra month between Hanukkah and Purim (15th of Adar).

[Seanette]

@Hari_Seldon

Not so. You will complete your 18th year at 7:59:59 on March 2 and not before. But we generally ignore the time of day. It is recorded in hospital records, I suppose but not on birth certificates.

Just checked the state-issued copies of DH’s and my birth certificates, both of us born in the 1960s. DH’s (from Mississippi) does not show the time he was born, mine (from Oregon) does.

[Monty]

@Max_S

Anyways in the U.S. the deal is, you’re one year older after 11:59pm February 28. Same standard used whether a leap year or not.

You wouldn’t happen to have a citation for this? I know the military does not adhere to what you’ve described.

[Francis_Vaughan]

@Saint_Cad

I remember reading about a court case. A person was fined for buying alcohol the day before his 21st birthday and the court ruled you were legally of age the day before your birthday. Based on my inability to find a reference to that case ever again, I wonder if it really happened.

I came in under this rule as a child. I take this on faith as told by my parents, because I was not yet 5. Which was the point. New year baby. The rule was that you had to have turned 5 the previous year to start school. So I lost by a day. Which was something of a blow as all the kids I knew in the neighbourhood, and had gone to kindergarten with, were starting school - and I wasn’t.
My Dad asked for some legal advice, and the answer was, there was case law, so a precedent. The son of a very wealthy family was killed in WW1 the day before his 21st birthday, and the day his share of the family fortune arrived. The ruling was that indeed, he was 21 on the day before his birthday, and thus the money was his, and passed on to his heirs.
So I got to go to school with my friends. The headmaster was not happy.

[Seanette]

My Google-fu is weaker than normal (had trouble figuring out good search terms), but found a couple of hopefully helpful links:

The Law Doesn't Care About February 29th

Leaping Through Time - The Leap Year Enigma - Bradley, Gmelich &...

[doreen]

I’m sure you got to go to school with your friends and the headmaster was not happy. I have no idea what the law is or was or if that’s what got you into first grade- but I don’t understand how you got into kindergarten if you would be too young for first grade when you finished. Or was it two different schools?

[Francis_Vaughan]

@doreen

but I don’t understand how you got into kindergarten if you would be too young for first grade when you finished. Or was it two different schools?

Kindergarten was a totally different thing to schools back then. It didn’t form part of the formal education system in the way things do now. Even now it is complicated here. There is government support for a fixed time before starting school proper. But nothing that says you can’t have more, and start earlier, if you pay the gap and go with a private entity. The line between preschool and day-care becomes blurred. And school start dates are not exactly straightforward either, with multiple start dates through the year…

[Petek]

US Social Security follows the rule that “A person attains a given age on the day before his corresponding birthday, i.e., the anniversary of his birth corresponding to that age.” See (SSR 63-15) and the citations therein.

[Max_S]

@Monty

@Max_S

Anyways in the U.S. the deal is, you’re one year older after 11:59pm February 28. Same standard used whether a leap year or not.

You wouldn’t happen to have a citation for this? I know the military does not adhere to what you’ve described.

There’s no single source as each state or even each legislative act (or administrative regulation) is technically free to have its own way of calculating age, so I’ll have to retract my initial answer.

Here are some cites:

March 1

Georgia: Ga. Code, § 15-11-6(b)

A child born on February 29 attains a specified age on March 1 of any year that is not a leap year.

Illinois: DelVecchio v. Illinois Dept. of Corr., 8 F.3d 509, 512 (7th Cir. 1993), reh’g en banc granted, opinion vacated (Dec. 17, 1993), on reh’g aff’d in part, rev’d in part on other grounds, sub nom. Del Vecchio v. Illinois Dept. of Corr., 31 F.3d 1363 (7th Cir. 1994)

DelVecchio was set to turn seventeen on March 1, 1965 (DelVecchio was born February 29, 1948, a leap year). Prosecutors, then, had they delayed sentencing for a few weeks, could have guaranteed that DelVecchio would serve time (and almost certainly more of it) in an adult institution. Here is the choice prosecutors faced: if DelVecchio were sentenced on February 28, 1965, he would go to a youth home and be eligible to be freed the next day; if he were sentenced on March 1, 1965, he would go to an adult penitentiary and receive a minimum mandatory sentence of fourteen years and possibly a sentence as high as fifty years.

Maine: Me. Rev. Stat. tit. 29-A, § 1406-A (3)

Leap year birthday. For the purposes of this section [drivers’ license], a person born on February 29th is deemed to have been born on March 1st.

Maryland: MD Code, General Provisions, § 1-303(b)

An individual born on February 29 attains a specified age on March 1 of any year that is not a leap year.

Michigan: M.C.L.A. 257.4a

“Birthday” shall mean any anniversary of the original date of birth, and all persons born on February 29 shall be deemed, for the purposes of this act, to have been born on March 1.

February 28

Nevada: Nev. Admin. Code 202.020

Unless suspended or revoked by the sheriff, a [concealed firearm] permit expires on the fifth anniversary of the permittee’s birthday, measured from the birthday nearest the date of issuance or renewal. If the date of birth of a permittee is on February 29 in a leap year, for the purposes of NRS 202.3653 to 202.369, inclusive, his or her date of birth shall be deemed to be on February 28.

Nev. Admin. Code 483.043

For the purposes of this chapter [drivers’ licenses and ID cards], any applicant, licensee or holder of an identification card whose date of birth was on February 29 in a leap year shall be deemed to have a birthdate of February 28.

Oregon: Or. Admin. R. 735-062-0007

A driver license issued to an applicant with a February 29 birthdate expires:
(a) On February 29 if the expiration year is a leap year; or
(b) On February 28 if the expiration year is not a leap year.

Or. Admin. R. 735-062-0010(10)

An identification card issued to a person with a February 29 birthdate expires:
(a) On February 29 if the expiration year is a leap year; or
(b) On February 28 if the expiration year is not a leap year.

Or. Admin. R. 735-062-0011

A Real ID identification card issued to a person with a February 29 birth date expires:
(a) On February 29 if the expiration year is a leap year; or
(b) On February 28 if the expiration year is not a leap year.

~Max

[Max_S]

@Petek

US Social Security follows the rule that “A person attains a given age on the day before his corresponding birthday, i.e., the anniversary of his birth corresponding to that age.” See (SSR 63-15 ) and the citations therein.

While not a lawyer, I will add that incrementing one’s age the day before the birthday is a legal fiction not adopted across the board (in the United States). Particularly it does not apply in a criminal context. See People v. Stevenson, 23 A.D.2d 472, 476, 262 N.Y.S.2d 238, 242 (1965) (Christ, J. dissenting), rev’d, 17 N.Y.2d 682, 216 N.E.2d 615 (1966).

~Max

[TokyoBayer]

@Monty

They start counting their age as another year on the first day of the year (also, they count the time their mother was pregnant with them as a whole year), but they celebrate their birthday on the anniversary of the actual day they were born.

Yeah, when I was teaching children in Taiwan, I would run into this all the time. Some of the kids would follow the older way of counting their age and others would use the same method as in the West, depending on what their parents or grandparents would tell them. You would have three different “ages” in a single class of first graders.

[Hari_Seldon]

The person who told me about the birthdays was an American born Israeli and quite religious, although not ultra-orthodox. The calendar hanging in our bedroom says at the top March/Adar I, Adar II, for what it’s worth.