# Birthday and International Date Line
**URL:** https://boards.straightdope.com/t/birthday-and-international-date-line/807715
**Category:** Miscellaneous and Personal Stuff I Must Share
**Created:** [January 29, 2018, 8:59am UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715 "2018-01-29T08:59:39Z")
**Posts on this page:** 14
**Page:** 1
### Author:  [@jtur88](https://boards.straightdope.com/u/jtur88)
#### Post date: [January 29, 2018, 8:59am UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/1 "2018-01-29T08:59:39Z")
The date of my birth was the 26th. But I have now moved across the International Date line, so on most of the 26th, it is still the 25th at the place I was born. So does my age advance on the date of birth at my place of birth, or the next day at the place where I am situated and subject to the laws of the land regarding age eligibility? To an observer where I am now, the newspaper date of my birth was the 27th.
Now, it gets complicated. I had previously crossed the International Date Line twice, both westward, and continued around the world without recrossing it back in the other direction, to unwind it. Those years, for me, had only 364 days. How do I reckon those two days in the calculation of my birthday? To I advance or retard my birthday by two days? Because of those two “days” that did not occur in my life, but passed as normal in the office holding my birth records.
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### Author:  [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)
#### Post date: [January 29, 2018, 10:10am UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/2 "2018-01-29T10:10:35Z")
Your DOB is the same date. The international date line is irrelevant, any move to a different time zone will result in the date being different for some period of the day between your place of birth and where you live.
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### Author:  [@BobLibDem](https://boards.straightdope.com/u/BobLibDem)
#### Post date: [January 29, 2018, 2:25pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/3 "2018-01-29T14:25:08Z")
I say live it up, bake a cake for both days.
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### Author:  [@GreenWyvern](https://boards.straightdope.com/u/GreenWyvern)
#### Post date: [January 29, 2018, 4:17pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/4 "2018-01-29T16:17:43Z")
I hate to think how you figure leap years into your birthday calculations…
In some years your birthday may be as much as 3/4 of a day out, because leap days are only added once every 4 years. Moreover, they are added at an arbitrary point in the calendar year. Do you have ‘leap birthdays’?
😉
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### Author:  [@kayaker](https://boards.straightdope.com/u/kayaker)
#### Post date: [January 29, 2018, 4:44pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/5 "2018-01-29T16:44:43Z")
For years now I’ve been celebrating either an intense birth_week_, or a more laid-back birth_month_. I didn’t realize people were still celebrating the blink-and-you’ve-missed-it birth_day_.
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### Author:  [@scr4](https://boards.straightdope.com/u/scr4)
#### Post date: [January 29, 2018, 7:02pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/6 "2018-01-29T19:02:52Z")
There’s nothing special about crossing the International Date Line. If you fly from Asia to Europe to America, you don’t cross the Date Line, but you’re still the same age as if you flew east from Asia straight to America. What matters is the time zone difference.
I live in a time zone 13 hours behind where I was born, so I’m entitled to start celebrating my birthday at 11am the previous day. (I don’t, though.)
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### Author:  [@Sunspace](https://boards.straightdope.com/u/Sunspace)
#### Post date: [January 29, 2018, 7:06pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/7 "2018-01-29T19:06:37Z")
> [@kayaker](#):
>
> For years now I’ve been celebrating either an intense birth_week_, or a more laid-back birth_month_. I didn’t realize people were still celebrating the blink-and-you’ve-missed-it birth_day_.
Some of us celebrate the birth_hour_. But not for long.
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### Author:  [@kayaker](https://boards.straightdope.com/u/kayaker)
#### Post date: [January 29, 2018, 7:10pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/8 "2018-01-29T19:10:28Z")
> [@scr4](#):
>
> There’s nothing special about crossing the International Date Line.
[Tell that to a sailor crossing for the first time.](https://randomwordstorm.wordpress.com/2015/02/19/how-sailors-celebrate-the-equator-or-international-date-line-crossing/)
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### Author:  [@Senegoid](https://boards.straightdope.com/u/Senegoid)
#### Post date: [January 29, 2018, 7:40pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/9 "2018-01-29T19:40:57Z")
If you can continue traveling non-stop around the world like that indefinitely, you can live forever!
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### Author:  [@Tim\_R.Mortiss](https://boards.straightdope.com/u/Tim_R.Mortiss)
#### Post date: [January 29, 2018, 8:01pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/10 "2018-01-29T20:01:36Z")
> [@kayaker](#):
>
> For years now I’ve been celebrating either an intense birth_week_, or a more laid-back birth_month_. I didn’t realize people were still celebrating the blink-and-you’ve-missed-it birth_day_.
I prefer celebrating my un-birthdays. There are a lot more of those!
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### Author:  [@TokyoBayer](https://boards.straightdope.com/u/TokyoBayer)
#### Post date: [January 29, 2018, 11:59pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/11 "2018-01-29T23:59:14Z")
One of my friends back in the States has a birthday one day after me. I would call him after 12:00 at night on my birthday and since it had already passed, he wouldn’t wish me a happy birthday. As it wasn’t his birthday yet in his location, I wouldn’t wish him one either.
Yes, we were weird that way.
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### Author:  [@jtur88](https://boards.straightdope.com/u/jtur88)
#### Post date: [January 30, 2018, 2:41am UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/12 "2018-01-30T02:41:56Z")
I actually landed once before I took off. My flight left Tokyo Thursday noon, and landed in Houston at 10-am Thursday. I had a two-hour Mulligan. Everybody gets a one-hour do-over, the night we turn back the clock.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [January 30, 2018, 7:28pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/13 "2018-01-30T19:28:51Z")
Every year, when my birthday approaches, I calculate which date it’s going to fall on this year. Due to Leap Year, it’s not always on the same date. And no, I wasn’t born on Leap Day, but it actually affects everyone; it’s just harder to ignore for Leap Day babies.
And there’s a famous science fiction book, _Ringworld_, which starts with the wealthy main character celebrating his birthday by rapidly traveling from city to city, with a party going in each, so he can stretch out his birthday to nearly two full days.
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### Author:  [@BwanaBob](https://boards.straightdope.com/u/BwanaBob)
#### Post date: [February 1, 2018, 5:01pm UTC](https://boards.straightdope.com/t/birthday-and-international-date-line/807715/14 "2018-02-01T17:01:50Z")
Figure out what the UTC date and time was the moment you were born. Adjust to your current time zone. Rinse Lather Repeat