# About Counting and time units **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [October 28, 2010, 12:13pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646 "2010-10-28T12:13:03Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Tiago44](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@Tiago44](https://boards.straightdope.com/u/Tiago44)\ **Post date:** [October 28, 2010, 12:13pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/1 "2010-10-28T12:13:03Z")
:smack:A child is born, he is in his first year until his first birthday, at this time he is one year old, and has begun his second year. A century is culminated at the end of the 100th year, and in the morning the next century is in its first year, or the first day after the 100th year. The first millennium was culminated at the year 1000, and the morning after was the beginning of the first year of the second millennium. Once anything is culminated it is not counted again, thus the beginning of the next is at completion of the first. Again, when you were one year old, you completed one year, and on your tenth birthcay at midnight you begin your eleventh year. Why is this concept so difficult to understand is quite beyond reason.:smack: ---
**Author:** ![davidm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/davidm/32/225_2.png) [@davidm](https://boards.straightdope.com/u/davidm)\ **Post date:** [October 28, 2010, 12:22pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/2 "2010-10-28T12:22:52Z")
Is this in response to a specific column? The usual practice is to include a link to the column in question ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [October 28, 2010, 12:59pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/3 "2010-10-28T12:59:43Z")
[The millennium approacheth. Will it start Jan. 1, 2000, or Jan. 1, 2001?](http://www.straightdope.com/columns/read/120/the-millennium-approacheth-will-it-start-jan-1-2000-or-jan-1-2001) (dated February 8, 1974) > [@Tiago44](#): > > The first millennium was culminated at the year 1000, and the morning after was the beginning of the first year of the second millennium. Ah yes, but at which end of the year 1000? (And my answer is December 31st – so the second millennium started on January 1st, 1001.) ---
**Author:** ![Vorpal\_Blade](https://avatars.discourse-cdn.com/v4/letter/v/9de0a6/32.png) [@Vorpal\_Blade](https://boards.straightdope.com/u/Vorpal_Blade)\ **Post date:** [October 28, 2010, 1:55pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/4 "2010-10-28T13:55:55Z")
> [@Tiago44](#): > > :smack:A child is born, he is in his first year until his first birthday, at this time he is one year old, and has begun his second year. > > A century is culminated at the end of the 100th year, and in the morning the next century is in its first year, or the first day after the 100th year. > > The first millennium was culminated at the year 1000, and the morning after was the beginning of the first year of the second millennium. > > Once anything is culminated it is not counted again, thus the beginning of the next is at completion of the first. > > Again, when you were one year old, you completed one year, and on your tenth birthcay at midnight you begin your eleventh year. > > Why is this concept so difficult to understand is quite beyond reason.:smack: Yawn… ---
**Author:** ![Tiago44](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@Tiago44](https://boards.straightdope.com/u/Tiago44)\ **Post date:** [October 28, 2010, 3:52pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/5 "2010-10-28T15:52:14Z")
Please read the post again, any given number is the sum to that specific point. January 1st would be the beginning of the second year of the millennium. The first entire year of the millennium will have culiminated at, for example, at midnight December 31, 2000, and the second year would commence immediately after midnight, the 1st of January. From January 1, 2000 until December 31, 2000 one is in the first year of the millennium. If this cannot be clearer, I apologize. ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [October 28, 2010, 3:59pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/6 "2010-10-28T15:59:34Z")
No. The reason why you are confused is probably because there was no Year 0. When the year 1 B.C. ended, the year A.D. 1 started. The first decade of the Christian era was A.D. 1 to A.D. 10, inclusive. The first century was 1 to 100, inclusive. The first millennium was 1 to 1000, inclusive. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 28, 2010, 4:31pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/7 "2010-10-28T16:31:09Z")
You said it yourself in the OP: > [@](#): > > A century is culminated at the end of the 100th year The 100th year is the year ending in 00. The end of the 100th year is Dec. 31, xx00. So the new century starts right after that, on Jan. 1, xx01. It is, indeed, a mystery why this is so difficult to understand. ---
**Author:** ![Indistinguishable](https://avatars.discourse-cdn.com/v4/letter/i/90ced4/32.png) [@Indistinguishable](https://boards.straightdope.com/u/Indistinguishable)\ **Post date:** [October 28, 2010, 5:21pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/8 "2010-10-28T17:21:45Z")
Well, the 100th year is the year ending in 00 just in case the 1st year is the year ending in 01. Which is certainly a natural thing to do, but of course you can count up from any point you like. I was perfectly happy to celebrate two millenia since 1 BC (i.e., New Year’s Eve 1999 -\> Near Year’s Day 2000) with more pomp and fanfare than two millenia since AD 1 (i.e., New Year’s Eve 2000 -\> New Year’s Day 2001); Jesus wasn’t really born in AD 1 anyway, so given that inaccuracy (and my lack of interest in Jesus’s birthdate regardless), what I’m really celebrating is the the niceness of seeing all the digits on the calendar turn over. ---
**Author:** ![Wheelz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wheelz/32/5718_2.png) [@Wheelz](https://boards.straightdope.com/u/Wheelz)\ **Post date:** [October 28, 2010, 7:13pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/9 "2010-10-28T19:13:39Z")
Really? People are still arguing about this? As far as I’m concerned, the correct aswer is: _Who Cares?_ The “starting point” was arbitrary. You can choose to measure any block of time from any equally arbitrary point. Therefore, 1001 through 2000 (inclusive) is a millenium. So is 1000 through 1999, or 1857 through 2856. July 17, 2003 through July 16, 2013 is a decade. 6:47:00 a.m. today through 6:46:59 a.m. tomorrow is a day. And so forth. \*It doesn’t matter. \* ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [October 28, 2010, 9:39pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/10 "2010-10-28T21:39:21Z")
> [@Tiago44](#): > > :smack:A child is born, he is in his first year until his first birthday, at this time he is one year old, and has begun his second year. > > A century is culminated at the end of the 100th year, and in the morning the next century is in its first year, or the first day after the 100th year. > > The first millennium was culminated at the year 1000, and the morning after was the beginning of the first year of the second millennium. > [@](#): > > Please read the post again, any given number is the sum to that specific point. January 1st would be the beginning of the second year of the millennium. The first entire year of the millennium will have culiminated at, for example, at midnight December 31, 2000, and the second year would commence immediately after midnight, the 1st of January. From January 1, 2000 until December 31, 2000 one is in the first year of the millennium. If this cannot be clearer, I apologize. According to your first post, it takes 100 years to make a century, and 1000 years to make a millennium. Since there was no year 0 AD, the first year AD was year 1. So the first century of AD is the year 1 through year 100, making year 101 the beginning of the second century AD. The first millennium AD started with they year 1, and ran through 1000 years, so that makes the last year the year 1000, and the beginning of the second millennium AD in 1001. Of course since this whole calendar was created long after the year 1 AD occurred, it’s pretty silly to worry about all this anyway. “For the purposes of conversation, the year 1 B.C. is the year 0 A.D., they are equivalent terms for the same thing.” Now everybody can be happy. ---
**Author:** ![qazwart](https://avatars.discourse-cdn.com/v4/letter/q/5fc32e/32.png) [@qazwart](https://boards.straightdope.com/u/qazwart)\ **Post date:** [October 29, 2010, 2:59am UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/11 "2010-10-29T02:59:57Z")
You know, when Jesus was born, people didn’t say “Let’s start the calendar all over again!” Instead, they kept counting their years pretty much as they always did: Either numbering them from the reign of the king, or since the founding of Rome. It wasn’t until what would now be calculated as the year 525 when a monk by the name of Dennis the Short used this method for calculating Easter. And his system of numbering years didn’t become popular until the eighth century. So, there was no Year 1 or Year 0. In fact, there was no Year 200 or Year 400. In fact, there wasn’t a year 524. And, when the year 700 and the year 701 rolled around, no most people didn’t stand around arguing when the new century started since they still weren’t counting the years by our current system. And, Dennis the Short wasn’t exactly accurate with his calculations either, so what he thought was the Year 1 probably wasn’t what should have been the Year 1. Since there’s no real way of calculating what should have been the start of the millennium, why not just go with the flow and say January 1, 2000 was the start of the millennium and that the start of all decades are evenly divisible by 10. Besides, the parties on January 1, 2000 were way better than the stuff that took place on January 1, 2001. ---
**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:** [October 29, 2010, 3:30pm UTC](https://boards.straightdope.com/t/about-counting-and-time-units/558646/12 "2010-10-29T15:30:46Z")
> [@qazwart](#): > > You know, when Jesus was born, people didn’t say “Let’s start the calendar all over again!” Instead, they kept counting their years pretty much as they always did: Either numbering them from the reign of the king, or since the founding of Rome. No, the Romans used the AUC dating about as often as we use “In the _nth_ Year of the Independence of the United States.” The normal reference was “In the year when _N.N.N._ and _N.N.N._ were consuls.” (Consuls continued to be elected for centuries after the effective end of the Republic.)