# Why 24 hours in a day and not some other number?
**URL:** https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679
**Category:** Factual Questions
**Created:** [May 29, 2004, 2:19pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679 "2004-05-29T14:19:05Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@wisernow](https://boards.straightdope.com/u/wisernow)
#### Post date: [May 29, 2004, 2:19pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/1 "2004-05-29T14:19:05Z")
OK…I have been thinking about it and need to know how and why it happened. Why and how did we get to have 24 hours in a day, and then 60 mins in an hour and then 60 secs in a minute? The concept of 1 year is comprehensible - I guess some bright and humble soul(possibly Egyptian? since they are the ones who spent a lot of time looking at the sky?) sometime in the past realized that planetary positions had a repetetive nature. So the time it took for all the stars in the sky to exactly in the same spot again, he called it 1 year. I can also perhaps understand the concept of 1 day. Same logic as before except that instead of the stars, this time around he decided to look at the sun. So far so good…my guess that is. This soul also wanted to divide that 1 day into smaller units perhaps. And now my brain decides to take a walk. What made him choose the weird figure of 24 units to divide the day? Why not a better and nice looking figure of say 10, or 25 or 100 or whatever? Further, why choose the figure of 60 to divide that 1 hour further into minutes? Having decided on that weirdo figure of 24, why not stick with it again and divide the hour into 24 minutes and the minute into 24 secs. Wouldn’t that be logically simpler? Why this fetish to intentionally defy Occam’s razor?
And finally if that makes sense why don’t change and adopt a simpler system now hust as we decided to go metric?
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### Author:  [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)
#### Post date: [May 29, 2004, 2:30pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/2 "2004-05-29T14:30:10Z")
> [@](#):
>
> Why are there 24 hours in a day? No one really knows. However, the tradition goes back a long way. Take, for example, this quote from Encyclopedia Britannica:
>
> ```
> "The earliest known sundial still preserved is an Egyptian shadow clock of green schist dating at least from the 8th century BC. It consists of a straight base with a raised crosspiece at one end. The base, on which is inscribed a scale of six time divisions, is placed in an east-west direction with the crosspiece at the east end in the morning and the west end in the afternoon. The shadow of the crosspiece on this base indicates the time. Clocks of this kind are still in use in primitive parts of Egypt. "
>
> ```
>
> The Babylonians seem to be the ones who started the six fetish, but it is not clear why.
> **[How Time Works](https://science.howstuffworks.com/science-vs-myth/everyday-myths/time2.htm)**
>
> Ever wonder why we start our year on the first of January? Or why we have January and the other 11 months in the first place? Find out all about time.
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### Author:  [@Cillasi](https://boards.straightdope.com/u/Cillasi)
#### Post date: [May 29, 2004, 2:35pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/3 "2004-05-29T14:35:52Z")
[http://www.1911encyclopedia.org/C/CA/CALENDAR.htm](http://www.1911encyclopedia.org/C/CA/CALENDAR.htm)
Everything you always wanted to know about our modern means of counting time and more - much, much more.
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### Author:  [@Cillasi](https://boards.straightdope.com/u/Cillasi)
#### Post date: [May 29, 2004, 2:40pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/4 "2004-05-29T14:40:53Z")
> [@Cillasi](#):
>
> [1911encyclopedia.org](http://www.1911encyclopedia.org/C/CA/CALENDAR.htm)
>
> Everything you always wanted to know about our modern means of counting time and more - much, much more.
Here’s an easier to understand site:
> **[Get ad-free, reliable email that's based on your own name |...](http://www.ernie.cummings.net/calendar.htm#THREE)**
>
> With RealNames, your email address is your name. You get email without ads that works with your favorite email program, in your web browser, and on your mobile phone or tablet.
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### Author:  [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)
#### Post date: [May 29, 2004, 2:43pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/5 "2004-05-29T14:43:42Z")
> [@wisernow](#):
>
> Why not a better and nice looking figure of say 10, or 25 or 100 or whatever?
Twelve is actually a very useful number as a basis for an everyday system, one which involved frequent mental arithmetic - it divides into 2, 3, 4 and 6. And 24 divides into 8. On the other hand, 10 only divides into 2 and 5.
ouldn’t that be logically simpler? Why this fetish to intentionally defy Occam’s razor?
> [@](#):
>
> And finally if that makes sense why don’t change and adopt a simpler system now hust as we decided to go metric?
Can you _imagine_ the complexity of that?
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### Author:  [@wisernow](https://boards.straightdope.com/u/wisernow)
#### Post date: [May 29, 2004, 3:00pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/6 "2004-05-29T15:00:10Z")
> [@GorillaMan](#):
>
> Twelve is actually a very useful number as a basis for an everyday system, one which involved frequent mental arithmetic - it divides into 2, 3, 4 and 6. And 24 divides into 8. On the other hand, 10 only divides into 2 and 5.
> ouldn’t that be logically simpler?
I am sorry but I do not understand how it is “logically” simpler. How does a number that divides into more numbers have anything to do with choosing that number to divide a day into? What and where is the benefit?
> [@GorillaMan](#):
>
> Can you _imagine_ the complexity of that?
Despite the initial problems we did change to metric for linear measurements, didn’t we? Why didn’t we also apply a similar reasoning to linear measurements? Like having 24 centimeters in a meter and 60 millimeters in a centimeter.
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### Author:  [@wisernow](https://boards.straightdope.com/u/wisernow)
#### Post date: [May 29, 2004, 3:02pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/7 "2004-05-29T15:02:04Z")
Thanks for the links. That answers my initial question of when and who did it. But what I wonder is what went on in the minds, their logic and reasoning into choosing such numbers of 24 and 60.
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### Author:  [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)
#### Post date: [May 29, 2004, 3:21pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/8 "2004-05-29T15:21:30Z")
Many people assume that ten is somehow a magic number. Not so.
We apparently settled on ten for our number system base, or radix, becuase we happen to have ten fingers and ten toes.
Some ancient groups counted in sixes and twelves. Now why did they pick such a “silly” number? They didn’t count fingers, but rather the spaces betwee them. You have one on the outside of your thumb, two between the thumb and index finger, three between index & middle finger, four between middle and ring finger, five between ring and little finger, and six on the outside of your little finger.
Thatr’s just as logical as the system we use.
There are legitimate mathematical advantages to using twelve rather than ten as the radix. As we become more computerized, even base sixteen has some value. Ten is acutally a pretty lousy choice of radix. But, like so many cultural things, they just happened that way and now we’re pretty well stuck with them.
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### Author:  [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)
#### Post date: [May 29, 2004, 6:46pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/9 "2004-05-29T18:46:30Z")
It’s crucial to remember that the Egyptians didn’t handle fractions the way we do. Their method is still called Egyptian fractions.
[Egyptian Fractions](http://www.ics.uci.edu/~eppstein/numth/egypt/)
> [@](#):
>
> Nowadays, we usually write non-integer numbers either as fractions (2/7) or decimals (0.285714). The floating point representation used in computers is another representation very similar to decimals. But the ancient Egyptians (as far as we can tell from the documents now surviving) used a number system based on unit fractions: fractions with one in the numerator. This idea let them represent numbers like 1/7 easily enough; other numbers such as 2/7 were represented as sums of unit fractions (e.g. 2/7 = 1/4 +1/28). Further, the same fraction could not be used twice (so 2/7 = 1/7 + 1/7 is not allowed). We call a formula representing a sum of distinct unit fractions an Egyptian fraction.
A culture disposed to thinking in unit fractions would naturally be guided to numbers that could be divided evenly by many others.
The changeover to the metric system and the resistance to changing to metric time is dealt with in a number of books. A fairly good recent one is the Poincare half of [Einstein’s Clocks, Poincare’s Maps: Empires of Time, by Peter Louis Galison](http://www.amazon.com/exec/obidos/tg/detail/-/0393020010/qid=1085856311/sr=1-1/ref=sr_1_1/104-0885610-5510352?v=glance&s=books).
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### Author:  [@C\_K\_Dexter\_Haven](https://boards.straightdope.com/u/C_K_Dexter_Haven)
#### Post date: [May 29, 2004, 7:44pm UTC](https://boards.straightdope.com/t/why-24-hours-in-a-day-and-not-some-other-number/247679/10 "2004-05-29T19:44:36Z")
So, here you are on the Straight Dope Message Board, and y’all give links to various explanations, and no one searches the Archives to see what Cecil has to say: [Who decided the day should be divided into 24 hours?](http://www.straightdope.com/classics/a1_125.html)