# Is 2/29 an invalid birth date?
**URL:** https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370
**Category:** Factual Questions
**Created:** [February 29, 2012, 6:18pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370 "2012-02-29T18:18:09Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@mangeorge](https://boards.straightdope.com/u/mangeorge)
#### Post date: [February 29, 2012, 6:18pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/1 "2012-02-29T18:18:09Z")
My boss announced that if a child is born on Februrary 29 the parents are required by the feds to choose between 2/28 and 3/01.
He heard it on the radio, probably talk radio.
Peace,
mangeorge
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### Author:  [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)
#### Post date: [February 29, 2012, 6:24pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/2 "2012-02-29T18:24:06Z")
A birth date includes the year. When you recognize your birthday is optional if you are a leap-year baby.
I call shenanigans.
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### Author:  [@friedo](https://boards.straightdope.com/u/friedo)
#### Post date: [February 29, 2012, 6:25pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/3 "2012-02-29T18:25:43Z")
Your boss is an idiot.
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### Author:  [@mangeorge](https://boards.straightdope.com/u/mangeorge)
#### Post date: [February 29, 2012, 6:31pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/4 "2012-02-29T18:31:00Z")
> [@friedo](#):
>
> Your boss is an idiot.
You know the Baby Jesus heard (read) that, right?
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### Author:  [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)
#### Post date: [February 29, 2012, 6:34pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/5 "2012-02-29T18:34:54Z")
That would be news to my husband, who was born on 2/29, and has that date on his drivers license.
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### Author:  [@Colophon](https://boards.straightdope.com/u/Colophon)
#### Post date: [February 29, 2012, 6:38pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/6 "2012-02-29T18:38:55Z")
In the UK (and I would assume 'most anywhere else) it’s perfectly valid. For legal purposes (e.g. attaining the age of majority) your birthday is considered to be March 1 in non-leap years.
I’m pretty sure that’s the normal practice - “choosing” February 28 would mean becoming older a day early. Marking the day on March 1 doesn’t make it a day late, as there’s no day in between.
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### Author:  [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)
#### Post date: [February 29, 2012, 6:52pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/7 "2012-02-29T18:52:32Z")
> [@Colophon](#):
>
> I’m pretty sure that’s the normal practice - “choosing” February 28 would mean becoming older a day early. Marking the day on March 1 doesn’t make it a day late, as there’s no day in between.
Yeah that makes a lot of sense if you consider the birthday to be “the day after the 28th of February.”
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### Author:  [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)
#### Post date: [February 29, 2012, 7:02pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/8 "2012-02-29T19:02:46Z")
Apparently, in the US, you’d mark it on February 28, at least [according to wiki](http://en.wikipedia.org/wiki/February_29) (I’m not sure if this is actually true).
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### Author:  [@robert\_columbia](https://boards.straightdope.com/u/robert_columbia)
#### Post date: [February 29, 2012, 7:06pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/9 "2012-02-29T19:06:48Z")
This is a plot device in Gilbert and Sullivan’s The Pirates of Penzance.
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### Author:  [@Skammer](https://boards.straightdope.com/u/Skammer)
#### Post date: [February 29, 2012, 7:08pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/10 "2012-02-29T19:08:24Z")
We’re celebrating my co-worker’s 14th birthday today. We were going to get her a Justin Bieber CD but her grandchildren said she wouldn’t like it.
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### Author:  [@Zsofia](https://boards.straightdope.com/u/Zsofia)
#### Post date: [February 29, 2012, 7:39pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/11 "2012-02-29T19:39:32Z")
> [@mangeorge](#):
>
> My boss announced that if a child is born on Februrary 29 the parents are required by the feds to choose between 2/28 and 3/01.
> He heard it on the radio, probably talk radio.
> Peace,
> mangeorge
My ex turned seven today. His driver’s license says 2/29, but often he has to put 2/28 on forms because it isn’t a valid date choice in software.
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### Author:  [@fiddlesticks](https://boards.straightdope.com/u/fiddlesticks)
#### Post date: [February 29, 2012, 7:42pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/12 "2012-02-29T19:42:52Z")
This is the top Google result for [leap day bug](http://www.rimmkaufman.com/blog/leap-day-bug/29022012/). So today is an invalid day to create a ads through the Bing system, apparently.
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### Author:  [@Leaffan](https://boards.straightdope.com/u/Leaffan)
#### Post date: [February 29, 2012, 7:48pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/13 "2012-02-29T19:48:01Z")
Well, I heard on the radio this morning too that a lot of insurance companies, etc. do not recognize 2/29 as a valid date of birth. I’m sure there are software systems out there that have accounted for this, but probably a lot of others that have not.
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### Author:  [@Marley23](https://boards.straightdope.com/u/Marley23)
#### Post date: [February 29, 2012, 7:50pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/14 "2012-02-29T19:50:06Z")
> [@Great\_Antibob](#):
>
> Apparently, in the US, you’d mark it on February 28, at least [according to wiki](http://en.wikipedia.org/wiki/February_29) (I’m not sure if this is actually true).
That’s not necessarily the date you’d _mark_ the birthday - that’s up to everybody individually - but if true, it’s an interesting note on the day the law recognizes your birthday. And even if it is correct that the law considers you 21 the day before your 21st birthday, I think there’s a good chance you would have trouble convincing a bar to serve you if you were out celebrating your birthday the day before.
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### Author:  [@Musicat](https://boards.straightdope.com/u/Musicat)
#### Post date: [February 29, 2012, 8:29pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/15 "2012-02-29T20:29:54Z")
> [@fiddlesticks](#):
>
> This is the top Google result for [leap day bug](http://www.rimmkaufman.com/blog/leap-day-bug/29022012/). So today is an invalid day to create a ads through the Bing system, apparently.
> [@Leaffan](#):
>
> Well, I heard on the radio this morning too that a lot of insurance companies, etc. do not recognize 2/29 as a valid date of birth. I’m sure there are software systems out there that have accounted for this, but probably a lot of others that have not.
As a programmer, I can tell you that accounting for this kind of error is one of the most trivial routines imaginable. To not do so is either ignorance or laziness. Don’t they teach the modern calendar in computer science class anymore?
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### Author:  [@tellyworth](https://boards.straightdope.com/u/tellyworth)
#### Post date: [February 29, 2012, 8:49pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/16 "2012-02-29T20:49:49Z")
> [@Musicat](#):
>
> As a programmer, I can tell you that accounting for this kind of error is one of the most trivial routines imaginable. To not do so is either ignorance or laziness.
This. Most modern development platforms and frameworks will include a date validation function that correctly handles leap years, and probably requires at most a few trivial lines of code. Failing to allow for Feb 29 suggests the programmer has written their own validation function, which means that not only did they get it wrong, they had to go to a considerable effort to do so.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [February 29, 2012, 9:02pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/17 "2012-02-29T21:02:44Z")
> [@](#):
>
> Yeah that makes a lot of sense if you consider the birthday to be “the day after the 28th of February.”
On the other hand, you could also consider the birthday to be “the day before the 1st of March”.
Really, the cleanest (though not simplest) way to handle it is to call your birthday the day on which you are an integer number of years old. Take the date _and time_ of your birth, add some multiple of 365.242199 days, and see what date this falls on. What most people don’t realize, though, is that if you do it this way, it actually affects the entire calendar, not just the end of February. For instance, about 3 years out of every 4 (including the year I was born), my birthday falls on April 29, but about 1 year out of 4, it falls on April 30.
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### Author:  [@psychonaut](https://boards.straightdope.com/u/psychonaut)
#### Post date: [February 29, 2012, 9:08pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/18 "2012-02-29T21:08:41Z")
> [@mangeorge](#):
>
> My boss announced that if a child is born on Februrary 29 the parents are required by the feds to choose between 2/28 and 3/01.
> He heard it on the radio, probably talk radio.
> Peace,
> mangeorge
> [@gotpasswords](#):
>
> That would be news to my husband, who was born on 2/29, and has that date on his drivers license.
But presumably the federal government didn’t issue his driver’s licence, so the OP’s scenario wouldn’t apply in this case.
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### Author:  [@Zsofia](https://boards.straightdope.com/u/Zsofia)
#### Post date: [February 29, 2012, 9:29pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/19 "2012-02-29T21:29:45Z")
> [@Marley23](#):
>
> That’s not necessarily the date you’d _mark_ the birthday - that’s up to everybody individually - but if true, it’s an interesting note on the day the law recognizes your birthday. And even if it is correct that the law considers you 21 the day before your 21st birthday, I think there’s a good chance you would have trouble convincing a bar to serve you if you were out celebrating your birthday the day before.
Actually, when he turned 25 we flew into Vegas on the 28th on a non-leap-year and I tried to have him put on the rental car with me. It required a manager to approve.
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### Author:  [@Musicat](https://boards.straightdope.com/u/Musicat)
#### Post date: [February 29, 2012, 9:38pm UTC](https://boards.straightdope.com/t/is-2-29-an-invalid-birth-date/614370/20 "2012-02-29T21:38:30Z")
> [@tellyworth](#):
>
> This. Most modern development platforms and frameworks will include a date validation function that correctly handles leap years, and probably requires at most a few trivial lines of code. Failing to allow for Feb 29 suggests the programmer has written their own validation function, which means that not only did they get it wrong, they had to go to a considerable effort to do so.
In the examples, a date was derived from a valid date plus a number, like {today’s date} + 10 years. This requires a validation and {IF DateNotValid…THEN…} decision block, even if it happens only once every 4 years, but the programmer didn’t realize that adding 10 years to some dates will result in an invalid date. My guess is that this validity test was omitted, and since it ran fine for almost 4 years, no one suspected the code was imperfect.
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