# leap year? **URL:** \ **Category:** Factual Questions\ **Created:** [December 13, 1999, 3:26am UTC](https://boards.straightdope.com/t/leap-year/5324 "1999-12-13T03:26:00Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![melanietarrant](https://avatars.discourse-cdn.com/v4/letter/m/898d66/32.png) [@melanietarrant](https://boards.straightdope.com/u/melanietarrant)\ **Post date:** [December 13, 1999, 3:26am UTC](https://boards.straightdope.com/t/leap-year/5324/1 "1999-12-13T03:26:00Z")
i’m confused? i’ve always heard that leap years were every 4 years except year that end on the 00 for example there was no leap year in 1900 but there was a leap year in 1896 and 1904 i also remember correctly answering a trivia question in 1996 “when is the next leap year?” i answered 2004 but i just got 2 calendars and both have february 29th are my calendars wrong? or am i confused? i need the help of people wiser than i!!! has anyone else ever heard the no leap year on the 'oo rule? ---
**Author:** ![Commander\_Fortune](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@Commander\_Fortune](https://boards.straightdope.com/u/Commander_Fortune)\ **Post date:** [December 13, 1999, 3:30am UTC](https://boards.straightdope.com/t/leap-year/5324/2 "1999-12-13T03:30:00Z")
Never heard that one before - My 2000 dayplanner has a 2/29/00. * * * She wasn’t sure what to do, so she looked at how the government did things and decided to run her life that way. ---
**Author:** ![rowrrbazzle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rowrrbazzle/32/414_2.png) [@rowrrbazzle](https://boards.straightdope.com/u/rowrrbazzle)\ **Post date:** [December 13, 1999, 3:34am UTC](https://boards.straightdope.com/t/leap-year/5324/3 "1999-12-13T03:34:00Z")
the rule for a year ending in 00 is that it must be divisible by 400 to be a leap year. So 1900 was not a leap year. 2000 is a leap year. 2100 is not, etc. ---
**Author:** ![Lord\_Jim](https://avatars.discourse-cdn.com/v4/letter/l/ecccb3/32.png) [@Lord\_Jim](https://boards.straightdope.com/u/Lord_Jim)\ **Post date:** [December 13, 1999, 3:39am UTC](https://boards.straightdope.com/t/leap-year/5324/4 "1999-12-13T03:39:00Z")
There are plenty of calendar discussions here, to get an in-depth discussion of it. But in general, yes, years divisible by 4 are leap years, except the century years, **except** the millenium year and it is a leap year. All comes from a balancing act of the Gregorian calendar to keep in sync with the sun. Now, duck. ---
**Author:** ![Lord\_Jim](https://avatars.discourse-cdn.com/v4/letter/l/ecccb3/32.png) [@Lord\_Jim](https://boards.straightdope.com/u/Lord_Jim)\ **Post date:** [December 13, 1999, 3:46am UTC](https://boards.straightdope.com/t/leap-year/5324/5 "1999-12-13T03:46:00Z")
Sorry, he’s right, I hurried a little too much. Every 400 years, not every millenium. ---
**Author:** ![melanietarrant](https://avatars.discourse-cdn.com/v4/letter/m/898d66/32.png) [@melanietarrant](https://boards.straightdope.com/u/melanietarrant)\ **Post date:** [December 13, 1999, 4:18am UTC](https://boards.straightdope.com/t/leap-year/5324/6 "1999-12-13T04:18:00Z")
thanks for the help folks, i got it now ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [December 13, 1999, 2:20pm UTC](https://boards.straightdope.com/t/leap-year/5324/7 "1999-12-13T14:20:00Z")
And just to muddy the waters a little more, the current convention will break down sometime between the year 3000 and 4000, when we will have accumulated one extra day. Someone has proposed that the year 4000 _not_ not be a leap year to correct that discrepancy (to keep with the “4” conventions–every fourth year is, only every fourth century is). We’ll see when it gets here, if there is a “we.” ---
**Author:** ![GuanoLad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guanolad/32/42_2.png) [@GuanoLad](https://boards.straightdope.com/u/GuanoLad)\ **Post date:** [December 13, 1999, 2:56pm UTC](https://boards.straightdope.com/t/leap-year/5324/8 "1999-12-13T14:56:00Z")
It is the very fact that 2000 is a leap year that makes it the Gregorian Calendar (Pope Gregory), and not the Julian Calendar (Julius Caesar) which failed to include that very proviso. 🙂 * * * -PIGEONMAN- Hero For A New Millennium! [The Legend Of PigeonMan](http://www.hotkey.net.au/~guanolad/pigeonman/) - updates every Wed & Sat. If I can be bothered. ---
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [December 13, 1999, 3:10pm UTC](https://boards.straightdope.com/t/leap-year/5324/9 "1999-12-13T15:10:00Z")
I once found an SD column about the rules and exceptions to the leap year. But _\strangely\_ the archive searcher isn’t working. It basically said:[list=1][li]a year has 365 days[/li][li]unless it’s divisible by 4, then it’s 366[/li][li]unless it’s divisible by 100, then it’s 365[/li][li]unless it’s divisible by 400, then it’s 366[/li]unless it’s divisible by 4000, then it’s 365[/list=1] ---
**Author:** ![John\_W.Kennedy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_w.kennedy/32/1031_2.png) [@John\_W.Kennedy](https://boards.straightdope.com/u/John_W.Kennedy)\ **Post date:** [December 13, 1999, 5:41pm UTC](https://boards.straightdope.com/t/leap-year/5324/10 "1999-12-13T17:41:00Z")
It appears that the 4000-year rule is not yet official (although tracking down an absolutely authoritative source on this vexing question is the very devil). Actually, if things stay as they are, the 4000-year rule won’t do; it’s an undercorrection, and after 20,000 years or so, will require an extra leap year to be left out. It would have been better to make every 2000 years not a leap year, to maintain the pattern of making each individual adjustment an overcorrection, but banks, _etc.,_ really don’t want their long-term calculations messed with. On the other hand, what with leap seconds, _etc.,_ corrections beyond the 400-year rule will probably have to be made on an _ad-hoc_ basis, anyway. * * * John W. Kennedy “Compact is becoming contract; man only earns and pays.” – Charles Williams ---
**Author:** ![Arjuna34](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@Arjuna34](https://boards.straightdope.com/u/Arjuna34)\ **Post date:** [December 14, 1999, 6:30am UTC](https://boards.straightdope.com/t/leap-year/5324/11 "1999-12-14T06:30:00Z")
Here is the absolutely authoritative source for Gregorian calendar: [http://personal.ecu.edu/mccartyr/inter-grav-text.html](http://personal.ecu.edu/mccartyr/inter-grav-text.html) There is some more info on it at [http://personal.ecu.edu/mccartyr/inter-grav.html.](http://personal.ecu.edu/mccartyr/inter-grav.html.) IIRC, most countries don’t actually restate the rules of the Gregorian calendar, they just specify “Gregorian.” Thus this papal bull is still the standard 🙂 (Of course this only applies to countries that use the Gregorian calendar). I don’t think there is a later international standard. There are ISO/IEC, etc. standards for date and time formats, but none for the calendar itself. Arjuna34 ---
**Author:** ![Boris\_B](https://avatars.discourse-cdn.com/v4/letter/b/fbc32d/32.png) [@Boris\_B](https://boards.straightdope.com/u/Boris_B)\ **Post date:** [December 14, 1999, 6:55am UTC](https://boards.straightdope.com/t/leap-year/5324/12 "1999-12-14T06:55:00Z")
My little neice or nephew is due around the end of February, and I was wondering, since this year is a “nested exception” (number 4 on AWB’s list), how many have there previously been? No, not since the Big Bang, since the invention of the Gregorian Calendar. If my calculations are correct, this will be the first “number 4 exception” in (British) New World. Which might make my niece/nephew a very special baby (I won’t give a durn about the little brat otherwize). ---
**Author:** ![Arjuna34](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@Arjuna34](https://boards.straightdope.com/u/Arjuna34)\ **Post date:** [December 13, 1999, 7:33pm UTC](https://boards.straightdope.com/t/leap-year/5324/13 "1999-12-13T19:33:00Z")
Since the Gregorian calendar was adopted in 1582, there has only been 1 year divisible by 400- the year 1600. PS- the second link in my last post incorrectly has a period at the end, as part of the link. The correct link is: [http://personal.ecu.edu/mccartyr/inter-grav.html](http://personal.ecu.edu/mccartyr/inter-grav.html) Arjuna34 ---
**Author:** ![Monty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/monty/32/47_2.png) [@Monty](https://boards.straightdope.com/u/Monty)\ **Post date:** [December 13, 1999, 9:05pm UTC](https://boards.straightdope.com/t/leap-year/5324/14 "1999-12-13T21:05:00Z")
> [@](#): > > i also remember correctly answering a trivia question in 1996 “when is the next leap year?” i answered 2004 Then, like your spelling, your answer was not correct. Please refer to the links provided above. ---
**Author:** ![C\_K\_Dexter\_Haven](https://avatars.discourse-cdn.com/v4/letter/c/b2d939/32.png) [@C\_K\_Dexter\_Haven](https://boards.straightdope.com/u/C_K_Dexter_Haven)\ **Post date:** [December 13, 1999, 11:16pm UTC](https://boards.straightdope.com/t/leap-year/5324/15 "1999-12-13T23:16:00Z")
Here’s the link to the Straight Dope Mailbag on this question: [Why do we have leap years?](http://www.straightdope.com/mailbag/mleapyr.html) ---
**Author:** ![melanietarrant](https://avatars.discourse-cdn.com/v4/letter/m/898d66/32.png) [@melanietarrant](https://boards.straightdope.com/u/melanietarrant)\ **Post date:** [December 14, 1999, 3:02am UTC](https://boards.straightdope.com/t/leap-year/5324/16 "1999-12-14T03:02:00Z")
wots rong with mi spelin? ---
**Author:** ![John\_W.Kennedy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_w.kennedy/32/1031_2.png) [@John\_W.Kennedy](https://boards.straightdope.com/u/John_W.Kennedy)\ **Post date:** [December 14, 1999, 4:47pm UTC](https://boards.straightdope.com/t/leap-year/5324/17 "1999-12-14T16:47:00Z")
Actually, the New Style calendar officially used by the United Kingdom (and probably by the United States, unless there has been some overriding statute passed) is _not_ the Gregorian Calendar. It is merely a fortunate (harumph! harumph!) coincidence that the evil papist Gregorian Calendar gives the same results as the Good and C of E New Style calendar. (I’m serious – the whole story is in the Britannica somewhere or other; a completely different mathematical system was worked out.) * * * John W. Kennedy “Compact is becoming contract; man only earns and pays.” – Charles Williams