Template talk:SI prefixes (infobox)

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Blue tableEdit

I've just edited the plain text version into the current blue table version, and am not totally happy with the result. However, I think it is an improvement on the previous version. It may need moving across to a Wiki table syntax, maybe tomorrow. Ian Cairns 21:52, 17 Oct 2004 (UTC)

Fixed spacingEdit

I've just centred the first column - since the fixed spacing was producing uneven results. I've also widened the Short Scale column since some rows were being forced onto two rows by the additional spaces. Hopefully, this may make the template look better to more people. Please note that just because it looks fine with fixed spacing to one person, it may not look the same to others with other Wiki skins. Thanks, Ian Cairns 23:52, 12 Dec 2004 (UTC)

kilo is k and not KEdit

Having just made the edit and subsequently investigated it, http://physics.nist.gov/cuu/Units/prefixes.html and http://www.bipm.fr/en/si/prefixes.html both support the fact that K is not the valid prefix for 1000.


What are people's thoughts to puting LaTeX maths into the table. This is inspired because 10002/3 makes me want to be physically sick! Fractions need to be on two line.   looks a lot better, but would look wierd if only a few were like that! So what's the general opinion?

I think it's fine the way it is. — Omegatron 17:52, 22 May 2007 (UTC)


I could not find any reference to the supposed prefixes "mancho" (1027) and "mincho" (10-27), so I removed them from the template. — Svenlafe 07:40, 20 June 2007 (UTC)


1960/1964/1975/1991 is from http://www.bipm.fr/en/si/prefixes.html (about SI proper), but maybe 1960 only marks the first use of the name "SI" with some units already in use since a CGPM predating 1960 (this should be investigated). 1795 (taken from the corresponding individual pages) is for some prefixes inherited from, originally, French legislation, although it should be investigated what the exact difference is between August 1, 1793 (apparently the real origin), April 7, 1795, and December 10, 1799. For (micro and?) mega, earlier dates are 1874 (cgs) and 1919 (mts), not verified. Giga also mentions 1947. Are there any other pre-SI dates for individual prefixes? How should they be represented in the table (choosing one, but which, or mentioning several)? Is there an article with a thorough history? — RFST 18:08, 10 November 2007 (UTC)

Added a note about what it is that we do have. Gene Nygaard 06:38, 15 November 2007 (UTC)
As you pointed out, the cgs systems existed for some time before the CGPM existed. Might need to look at the usage of its pioneers such as Gauss if you want to try to find earlier usage. I agree that micro- and mega- in particular saw considerable use before the dates given here. Gene Nygaard 06:40, 15 November 2007 (UTC)
The official introduction year for micro and mega is 1873. These prefixes were 'recommended' in the 'First Report of the Committee for the Selection and Nomenclature of Dynamical and Electrical Units' (1873) of the British Association for Advancement of Science, as part of the Centimetre–gram–second system of units:"For multiplication or division by a million, the prefixes mega and micro may conveniently be employed, according to the present custom of electricians. Thus the megohm is a million ohms, and the microfarad is the millionth part of a farad. [1] Ceinturion (talk) 11:26, 3 August 2015 (UTC)

Citation needed tagsEdit

The web site http://physics.nist.gov/Pubs/SP330/sp330.pdf, titled NIST Special Publication 330: The International System of Units, published in 2001 by the National Institute of Standards and Technology verifies that the CGPM first met in 1889 (page 2) and that the definiton of the micron was abrogated by the 13th CGPM (1967-8) (page 42). Therefore I am removing the citation needed tags. It is not practical to put a citation in a template, since the articles that incorporate it will have different citation styles. --Gerry Ashton (talk) 00:40, 16 December 2007 (UTC)

Da or Dk?Edit

I am a student in school, and they taught deca- as deka. We also learned the symbol as Dk. Could someone check to find which one is right? (talk) 00:27, 1 February 2009 (UTC)

Deka- is American for deca- but I think "Dk" is just wrong, it's "da" (lower case). JIMp talk·cont 05:21, 14 February 2012 (UTC)

Incomplete data setEdit

Please include the following:

10^27 - xona (X)
10^30 - weka (W)
10^33 - vunda (V)
10^36 - uda (U)
10^39 - treda (TD)
10^42 - sorta (S)
10^45 - rinta (R)
10^48 - quexa (Q)
10^51 - pepta (PP)
10^54 - ocha (O)
10^57 - nena (N)
10^60 - minga (MI)
10^63 - luma (L)

Source: http://plexos.com/256_bit_CPUs_should_be_enough.htm —Preceding unsigned comment added by (talk) 08:50, 19 February 2010 (UTC)

Scientific notationEdit

I've just deleted the "Scientific notation" column added by an anon last November. This was not scientific notation as such but e notation ... okay e notation is actually a form of scientific notation but the standard form is ×10n which we should prefer and which we already have. The e notation added nothing to the table: who's going to understand e notation if they don't get standard scientific notation? JIMp talk·cont 05:20, 14 February 2012 (UTC)

The Long Scale is dead in English.Edit


The "long scale" isn't completely dead. There are a few of us sticklers who remember what a billion really is. But I'm not about to revert the recent deletion of the long scale column. For better or worse, if not completely dead in English, the long scale is pretty much dead on Wikipedia and us clingers on to the more logical original definitions are having to cop it sweet just about everywhere else. It's not ambiguous either since the numbers are written out as powers of a thousand and of ten and as decimals. So is it really worth the clutter of returning the long scale column for the benefit of a few sticks in the mud? JIMp talk·cont 03:30, 23 March 2013 (UTC)

Tiny reference(s)Edit

The list of references within the table is currently rendered as CSS font-size:xx-small, which makes it unnecessarily difficult to read. I'm going to adjust that to only x-small, still two steps smaller than the main text.  Unician   19:41, 14 May 2014 (UTC)

That's an improvement, if you go and make them bigger still, don't expect any complaints from me. Jimp 10:29, 15 May 2014 (UTC)
I think I'll stop at x-small for now; when I tested size small, the footnote text reached the right border and wrapped on to a second line.  Unician   21:20, 17 May 2014 (UTC)

Six original prefixes?Edit

I believe that the original 1795 metric system included eight prefixes, the six familiar ones plus myria (10**4, "ma") and myrio (10**-4, "mo"). So the footnote is at least misleading as written. I suggest changing the first sentence in to footnote to either "The metric system was introduced in 1795 with eight metric prefixes, six of which are still in use." or "Six of the prefixes were introduced with the metric system in 1795."

There were also other prefixes that have appeared but have fallen out of use, but I think we can ignore those. Rwessel (talk) 03:48, 20 June 2015 (UTC)

I removed myrio because it is not supported by references. Ceinturion (talk) 12:24, 17 September 2015 (UTC)


I rewrote the footnote because the title of the table is 'SI prefixes', not 'metric prefixes'. I removed some clutter from the 'adoption year' column as well. As the table is transcluded into many articles it should not contain excessive detail. Compare, for example, the much cleaner metric prefixes template, which does not need a footnote at all. Ceinturion (talk) 14:38, 28 April 2017 (UTC)


The table currently suggests the word "one" can be substituted for the prefix of the generic unit. To me, that does not seem to be right. For comparison, "2 kilogram is two thousand gram", and "2 milligram is two thousandth of a gram": in those examples the word can be substituted for the prefix. However, the word "one" is not a valid substitute; 2 gram cannot be replaced by "two one gram". Hence, the table should contain a dash. Ceinturion (talk) 16:49, 20 July 2019 (UTC)

This argument does not make sense to me. English substitution is not a robust test, and your choice of construction is not the only possible one. Besides, it would also eliminate "ten": 2 decagram cannot be replaced by "two ten gram". The word in the column might be best understood as the answer to "By what number does the prefix notation multiply a unit?", and all the words fit (aside from the trivial prefixing of "a" or "one"). Your test really tests for when the English word accepts a prefixed multiplier word, not whether it can act as a multiplier: we say "one hundred birds" and "two tenths inches", but "ten birds" and "one bird". —Quondum 21:49, 20 July 2019 (UTC)
Thanks for the explanation, Ceinturion (talk) 23:50, 20 July 2019 (UTC)

Aligned decimals?Edit

I experimented with using the {{decimal cell}} template to align the decimals in my sandbox. I'm thinking about substituting this in. I would prefer to keep the {{gaps}}, but haven't found a way to make that work. Other users' thoughts and suggestions are welcome. Feel free to tinker with the copy in my sandbox.--Srleffler (talk) 03:07, 21 July 2019 (UTC)

The increase in width is quite a price to pay for the alignment, though I take no particular position on this. I would suggest removing the decimal point from the integer values. Not sure why it displays a column break in your sandbox (not there in the template's example); this and the lack of thousands separator add an element of clumsiness. The thousands break would be best fixed by supporting such an option in the {{decimal cell}} template. —Quondum 17:26, 21 July 2019 (UTC)
I included the trailing decimal because I assumed the decimal cell template needed it, but I see now that it does not. I agree that if we were going to use this, it would make sense to make a version of the decimal cell template with the gaps functionality built in. That's not a trivial exercise, though.--Srleffler (talk) 17:57, 21 July 2019 (UTC)
I've managed to tweak the table in your sandbox to what I think you were trying to achieve. However, we still haven't tackled the question of whether the width is worth it. —Quondum 02:29, 22 July 2019 (UTC)
I see, thanks. I don't have any opinion one way or the other about the width. Looking forward to see what others think.--Srleffler (talk) 03:05, 22 July 2019 (UTC)
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