# In the 1000s: K? M? and MM?
**URL:** https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455
**Category:** Factual Questions
**Created:** [April 19, 2002, 2:57am UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455 "2002-04-19T02:57:23Z")
**Posts on this page:** 19
**Page:** 1
### Author:  [@Jinx](https://boards.straightdope.com/u/Jinx)
#### Post date: [April 19, 2002, 2:57am UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/1 "2002-04-19T02:57:23Z")
When dollar figures, and such, are in the thousands, why is it proper to express as EITHER K? or M? and why do we need MM for millions? K is and always has meant 1000s!!! M is millions!
Now, we mix in M for K and MM for M! How stupid!
(Like, for those in HVAC: MBUH for thousands of BTUs/hr??? Or, those in finance: A CEO makes $100MM???)
What’s the deal, and how do you what they really mean?
- Jinx
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### Author:  [@Popup](https://boards.straightdope.com/u/Popup)
#### Post date: [April 19, 2002, 9:48am UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/2 "2002-04-19T09:48:29Z")
Well, it’s a long story.
Basically it’s the romans fault. They used ‘M’ for ‘mille’ (or whatever it might be in latin - thousand) It is sometimes written with lowercase ‘m’. And to confuse things further the roman symbol for million is also ‘M’, but under- and ‘over-’ lined.
Then when the ISO standardisation got started it was decided to use ‘k’ for thousand, ‘m’ for 1/1000 and ‘M’ for million.
It gets even worse nowadays when people mix binary and decimal prefixes.
Search the arcives for the reason why you should avoid calling a 3.5" (actually 90mm) floppy 1.44Mb!.
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### Author:  [@Achernar](https://boards.straightdope.com/u/Achernar)
#### Post date: [April 19, 2002, 9:58am UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/3 "2002-04-19T09:58:52Z")
You should switch to metric. In metric, k always means thousand, and M always means million. Of course, then you’d have to get used to G meaning billion.
As for knowing what they really mean, have you ever really had a time when it wasn’t clear from context? I mean come on, there’s a big difference between $1,000 and $1,000,000.
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### Author:  [@Balor](https://boards.straightdope.com/u/Balor)
#### Post date: [April 19, 2002, 11:06am UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/4 "2002-04-19T11:06:36Z")
M is of course just the Roman numeral for 1000. They did not use the Arabic system that is standard today. So MMII meant 1000 plus 1000 plus 1 plus 1 - that is 2002. If you want to talk mean about the Arabs, you better stop using their numbering system first.
For the use of “k”, you can blame the Greeks, but mainly the French.
In ancient Greek, the word for “thousand” is"chilioi". It starts wth the letter chi, a hard “ch” like in “school”. So it sounds like kilioi.
The French introduced the Metric system around 1795, after their Revolution, with new measures like grammes, metres and litres. BTW - the inventors spelt them that way. Americans are out of step in calling them grams, meters and liters.
To express multiples of the new measures, they used Greek prefixes. “Deka” in Greek was ten, so a decagramme was ten grammes. For a thousand of something, they used “kilo”. Strictly, it should have been “chilo”, but they were practical about it. So, a kilogramme was a thousand grammes.
People today rarely use prefixes other than “kilo” - grammes and kilogrammes, metres and kilometres. These are written as g and kg, m and km. So “k” has come to mean “a thousand of something being measured”.
This has been transferred to money. $100k was used for $100, 000. To be logical about it, we should have used the Roman M, but this would have been confusing, since it also means million and mile and metre and so on.
So, “k” has come to mean 1000.
QED - Quod erat demonstrandum, as we used to say in those old days in Rome. Ah, those were the days amicus meus.
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### Author:  [@Schnitte](https://boards.straightdope.com/u/Schnitte)
#### Post date: [April 19, 2002, 1:25pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/5 "2002-04-19T13:25:33Z")
> [@](#):
>
> Ah, those were the days amicus meus.
[nitpick]
Don’t you need the vocative here? Amice? 😛
[/nitpick]
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### Author:  [@Monty](https://boards.straightdope.com/u/Monty)
#### Post date: [April 19, 2002, 1:39pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/6 "2002-04-19T13:39:00Z")
Is and always, huh? Metric system uses the prefix _kilo_ to mean thousands. It also uses the prefix _milli_ to mean thousands. The difference is that the Greek loan word is used to indicate multiples and the Latin loan word is used to indicate divisions of the basic unit to which the prefix is affixed.
Regarding the assertion that people rarely use the other prefixes: millimeteres and centimeters get used a lot.
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### Author:  [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)
#### Post date: [April 19, 2002, 2:06pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/7 "2002-04-19T14:06:37Z")
Megabytes, anyone? Gigabytes? Heck, I can already see that terabytes will become common in a few years.
(And, yes, I know that 1000 != 1024.)
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### Author:  [@Balor](https://boards.straightdope.com/u/Balor)
#### Post date: [April 19, 2002, 2:22pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/8 "2002-04-19T14:22:49Z")
> [@](#):
>
> \*Originally posted by Schnitte \*
> \*\*
>
> [nitpick]
> Don’t you need the vocative here? Amice? 😛
> [/nitpick] \*\*
I abase myself before you. Domine, non sum dignus. . .
You are of course correct, and my Latin teacher is now spinning in his grave.
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### Author:  [@Balor](https://boards.straightdope.com/u/Balor)
#### Post date: [April 19, 2002, 2:43pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/9 "2002-04-19T14:43:27Z")
> [@](#):
>
> \*Originally posted by Monty \*
> \*\*The difference is that the Greek loan word is used to indicate multiples and the Latin loan word is used to indicate divisions of the basic unit to which the prefix is affixed.
>
> Regarding the assertion that people rarely use the other prefixes: millimeteres and centimeters get used a lot. \*\*
I agree that most of the latin prefixes are commonly used in divisions, as you suggest. We see decilitres as well as cm and mm.
I was dealing with letter “k” and kilos, so for the sake of brevity I actually deleted a couple of paragraphs which said roughly what you say above about divisions. I felt it was not relevant to the point in discussion.
In dealing with multiples, people do not normally refer to decagrammes or decametres although such a measure exists in theory. Instead, they usually measure weights in either “kilos” or grammes, and distances in metres and kilometres.
So the “k” has become a popular abbreviation for 1000. And by extension they now use it in kilobytes, although there are in fact 1024 bytes as Terminus Est points out.
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### Author:  [@Schnitte](https://boards.straightdope.com/u/Schnitte)
#### Post date: [April 19, 2002, 3:03pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/10 "2002-04-19T15:03:49Z")
Breweries often state their beer output in hectolitres.
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### Author:  [@Balor](https://boards.straightdope.com/u/Balor)
#### Post date: [April 19, 2002, 3:15pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/11 "2002-04-19T15:15:43Z")
But drinkers state their beer input in litres.🙂
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### Author:  [@Schnitte](https://boards.straightdope.com/u/Schnitte)
#### Post date: [April 19, 2002, 3:17pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/12 "2002-04-19T15:17:41Z")
That’s right. Thankfully.
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### Author:  [@Capt.Nemo](https://boards.straightdope.com/u/Capt.Nemo)
#### Post date: [April 20, 2002, 5:24pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/13 "2002-04-20T17:24:00Z")
A common American civil engineering term is “kip” or 1,000 pounds.
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### Author:  [@AWB](https://boards.straightdope.com/u/AWB)
#### Post date: [April 20, 2002, 11:13pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/14 "2002-04-20T23:13:52Z")
“G” is also used for $1000, especially in gambling circles.
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### Author:  [@Derleth](https://boards.straightdope.com/u/Derleth)
#### Post date: [April 21, 2002, 4:13am UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/15 "2002-04-21T04:13:55Z")
In the drug business, a thousand dollars is a key. As in K.
As in, “I have ten keys in pure coke here. How much should I cut it?”
At least it is in the movies.
😃
(A _thousand_ dollars is a G? Shouldn’t that be a _billion_?
K = kilo = thousand (n_10[sup]3[/sup])
M = meg(a) = million (n_10[sup]6[/sup])
G = gig(a) = billion (n\*10[sup]9[/sup])
For most computer applications, assume similar progressions but in base-two (two as the number you take powers of) unless it’s in sales, in which case it’s up in the air. Base-two megs are larger than base-ten megs.)
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### Author:  [@Achernar](https://boards.straightdope.com/u/Achernar)
#### Post date: [April 21, 2002, 4:52am UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/16 "2002-04-21T04:52:18Z")
**Derleth** , G is short for “grand,” which is slang for a kilobuck.
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### Author:  [@Derleth](https://boards.straightdope.com/u/Derleth)
#### Post date: [April 21, 2002, 6:54am UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/17 "2002-04-21T06:54:31Z")
**Achernar** : OK. That makes sense.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [April 21, 2002, 6:51pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/18 "2002-04-21T18:51:52Z")
Quoth **Monty** :
> [@](#):
>
> Is and always, huh? Metric system uses the prefix kilo to mean thousands. It also uses the prefix _milli_ to mean thousands.
No, it uses the prefix “milli” to mean thousand **th** s. A millimeter is not 1000 meters, it’s 0.001 meter.
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### Author:  [@Monty](https://boards.straightdope.com/u/Monty)
#### Post date: [April 21, 2002, 8:32pm UTC](https://boards.straightdope.com/t/in-the-1000s-k-m-and-mm/104455/19 "2002-04-21T20:32:34Z")
Chronos:
Next time don’t leave out
> [@](#):
>
> The difference is that the Greek loan word is used to indicate multiples and the Latin loan word is used to indicate divisions of the basic unit to which the prefix is affixed.
where I clearly indicated that the milli is used for thousandths.
Unless, of course, you have a different definition of “divisions” than the rest of us.