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 about units: 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  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  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. See also 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 traditional symbol for one million Btu (about 1.055 057 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. Information or Babel? - Madnick 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 Financial/M&A Advisor 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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