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### K as an Abbreviation for Thousands

```Date: 05/29/2002 at 21:48:38
From: Caryll
Subject: Representation of thousands and millions

In class last night my professor wrote \$30M and intended it to
mean thirty thousand dollars.  I was taught that 30K meant thirty
thousand.  I looked at several of the sites referencing Roman
numerals, but can't find anything about 'K'.  Can you assist?
```

```
Date: 05/29/2002 at 22:47:10
From: Doctor Peterson
Subject: Re: Representation of thousands and millions

Hi, Caryll.

When we write "30 K" for 30,000, we are not using Roman numerals
but pseudo-metric, where K stands for "kilo-".

For the same reason, "30 M" means 30,000,000, using M for "mega-"
(or just "million").

It would be wrong to use Roman numerals this way; M here can't
stand for thousand. But I suspect it's a common mistake.

See this site, listed in our FAQ, that tells all there is to know

How Many?
http://www.unc.edu/~rowlett/units/

K
an informal abbreviation for one thousand used in
expressions where the unit is understood, such as "10K
run" (10 kilometers) or "700K disk" (700 kilobytes or
kibibytes). Note that "K" is also the symbol for the
kelvin (see below). Also note that the symbol for the
metric prefix kilo- (1000) is actually k-, not K-.

M [1]
informal abbreviation for million in expressions where
the base unit is understood, as in "500M hard drive"
(500 megabytes or mebibytes). In chemistry, M is the
symbol for "molar" (see below).

M [2]
the Roman numeral 1000, sometimes used in symbols to
indicate a thousand, as in Mcf, a traditional symbol
for 1000 cubic feet. Given the widespread use of M to
mean one million, this older use of M to mean 1000 is
very confusing and should be scrapped.

Is K a Roman numeral?
http://mathforum.org/library/drmath/view/58754.html

- Doctor Peterson, The Math Forum
http://mathforum.org/dr.math/
```

```
Date: 05/30/2002 at 08:04:43
From: Caryll
Subject: Thank you (Representation of thousands and millions)

Many thanks for the clarification.  Keep up the good work.
```

```
Date: 10/08/2002 at 15:25:33
From: Chris Chang
Subject: On M representing Thousands

I believe it is incorrect for you to state that usage of M,
such as \$10M, is wrong to represent thousands.

While \$10K is more common, there has certainly been a
convention for many years in various businesses for
\$10M to mean \$10,000 and for \$10MM to mean \$10,000,000.

This is a confusing issue because to my knowledge there
is no definitive standard. Instead, convention has varied
by field, and case to case. Indeed I am sure there are
different people right now using M to mean thousands
while others are using it to mean millions.

I suggest checking the convention in a specific situation.

Chris Chang
```

```
Date: 10/08/2002 at 15:35:04
From: Doctor Peterson
Subject: Re: On M representing Thousands

Hi, Chris.

Can you give  me any references to show this usage, either a manual
of some sort, or an example (preferably on the Web so I can see it
easily)? I will still stand by my statement that it is "wrong,"
because as you admit it is very confusing; but as we know many things
that are wrong are nevertheless standard, and it would be good to
point that out in case people confuse the two concepts.

Also, note that I referred to Russ Rowlett's page, where he says that
M for thousand IS used, but should be eliminated, which is what I am
saying too. Neither of us claims that it is only used mistakenly,
just that it is not a good idea.

The references I found some from government and industry, often in
energy or forest related fields where Rowlett's "Mcf" is also found:

Glossary - Southern Appalachian Forest Coalition
http://www.safc.org/resources/glossary.htm

M - thousand
M\$ - thousands of dollars
MAUM - thousand animal unit month
MBF - thousand board feet
MCF - thousand cubic feet
MM - million
MM\$ - millions of dollars
MMBF - million board feet
MMCF - million cubic feet
MMRVD - million recreation visitor-day

Energy INFOcard
http://www.eia.doe.gov/neic/brochure/infocard00.htm

MMbd = million barrels per day; Mcf = thousand cubic feet
tcf = trillion cubic feet; kWh = kilowatthour; MM = million

Fuel Alcohol Plant Cost Study Cases
http://www.dnr.state.la.us/sec/execdiv/techasmt/lep/fal87/016.htm

CAPITAL COSTS
M=Thousand
MM=Million

\$25 MM

The frequent coexistence of MM in money and in unit names suggests
that in fields where such obsolescent units are used, the habit
carries over into financial notation.

I can also refer to these entries in Rowlett that I had missed; they
confirm my impression of the industries affected:

MM
an abbreviation for one million, seen in a few traditional
units such as those listed below. The abbreviation is meant
to indicate one thousand thousand, M being the Roman numeral
1000. However, MM actually means 2000, not one million, in
Roman numeration.

MMb, MMbo
symbols for one million barrels of oil; see megabarrel above.

MMBF or MMBM
symbols sometimes used in U.S. forestry for one million board
feet. One MMBF represents a volume of 83 333 cubic feet or
2360 cubic meters. "BM" stands for "board measure."

MM Btu
gigajoules (GJ)), a unit used widely in the energy industry.
This unit is also called the dekatherm.

MMCF
a symbol for one million cubic feet (28 316.85 m3, or
28.316 85 megaliters).

MM scfd
symbol for one million standard cubic feet per day, the
customary unit for measuring the production and flow of
natural gas. "Standard" means that the measurement is
adjusted to standard temperature (60 °F or 15.6 °C) and
pressure (1 atmosphere).

As much as I dislike this notation, I certainly have to admit that
it is still current in some fields, and has to be lived with for
now. The professor in the original question has the final say.

Thanks for pointing out this interesting backwater of notation!

- Doctor Peterson, The Math Forum
http://mathforum.org/dr.math/
```

```
Date: 10/08/2002 at 16:38:52
From: Chris Chang
Subject: On M representing Thousands

I agree with you that it would be nice to get rid of MM representing
millions and simply use M, or any sort of standardization so we know
what people mean!

I was specifically thinking of the financial industry, which your
Rowlett citation mentions, where MM is still in regular use.
Admittedly, now that I look around and think about it, I have not
seen M used much recently - primarily because figures tend to be
larger and so are not often quoted in thousands.

A few references follow:

Done Deals Definitions
http://donedeals.nvst.com/definitions.asp
A site that uses M for thousands and MM for millions.

Merrill Lynch glossary
http://www.fs.ml.com/help/glossary.asp?term=m
Merrill Lynch glossary.
See Market Cap entry, uses \$MM for millions of dollars.
Median Market Cap uses \$M for thousands of dollars, although
definition of \$M is not stated explicitly.

http://www.vxm.com/21R.68.html
section 2.1 paragraph 3:
(as an aside, even if given a clue, such as 23M, there may be a
problem because sometimes M means millions, sometimes it means
thousands - in which case MM is used to mean millions)
Exactly the various usage we are talking about.

7-11 Financial Report
http://www.7-eleven.com/investing/financialdata_incomestatement.asp
This financial report just uses MM for millions.

Yale Career Information Center
http://www.som.yale.edu/careers/cic/resume_tips.asp
This Yale guide uses K for thousands, M to mean one million, and MM
to represent millions.  This seems even more confusing to me, but
goes to my point that there is a lot of different usage around.

Chris
```

```
Date: 01/17/2003 at 18:16:31
From: Richard Wilkes
Subject: Recent article on the letter M

I noted with agreement your statement that "K" refers to thousands,
"M" to millions. However, it is not uncommon in the business world to
see "M" for thousands, "MM" for millions, and "MMM" for billions.
This probably is a fairly recent trend/shortcut in finance. The same
holds true for dashes, such as one the length of a hyphen, used as a
superscript above and right of the number (as one would in noting that
a number has been squared or cubed, for example). I have seen (and
have used myself when writing down numbers) one (superscript) dash for
thousands, two for millions, three for billions, and so on.

Richard Wilkes
Houston, TX
```

```
Date: 10/01/2005 at 18:22:29
From: George
Subject: K as an Abbreviation for Thousands

You mention a preference for the use of "K" rather than "M" for
thousands.  I have been in and around the printing industry for over
twenty five years.  In our industry, it is true that K is the
standard used to indicate thousands in some parts of the world, and
M is the standard used in others, including the United States.  Until
a consensus is reached, I agree that it could be confusing; however,
until that time, there is an easy way to avoid that confusion. Don't
focus on changing the symbol for thousands, which would be both
difficult and time consuming, considering the various cultural
predispositions.  Instead, always use MM for millions.  That way neither
K nor M would be mistaken for millions in my industry as well as
many others.

```

```
Date: 10/01/2005 at 21:15:12
From: Doctor Peterson
Subject: Re: K as an Abbreviation for Thousands

Hi, George.

That's not a bad thought; though if you use M for thousands, that
could still be mistaken for millions until the reader notices that you
are using MM for that purpose. If you go further and use only K and
MM, you could avoid ambiguity entirely (as long as your audience is
not so stuck on one tradition that they don't recognize the other). On
the other hand, your rule just takes two individually logical systems
and combines them into a hybrid that makes no sense, and that would
have to be replaced eventually anyway if we want to migrate to a
single consistent system. I don't quite like it, but could probably
live with it if I had to!

I think there will always be some confusion, but your idea is a
possibility for reducing it.

- Doctor Peterson, The Math Forum
http://mathforum.org/dr.math/
```
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