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Template talk:SI prefixes (infobox)

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Blue table[edit]

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 spacing[edit]

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 K[edit]

Having just made the edit and subsequently investigated it, and 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)[reply]


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)[reply]


1960/1964/1975/1991 is from (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)[reply]

Added a note about what it is that we do have. Gene Nygaard 06:38, 15 November 2007 (UTC)[reply]
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)[reply]
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)[reply]

Citation needed tags[edit]

The web site, 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)[reply]

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)[reply]

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)[reply]

Incomplete data set[edit]

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: —Preceding unsigned comment added by (talk) 08:50, 19 February 2010 (UTC)[reply]

this link appears to be dead, do you have a different source? I could not find anything that would indicate this list is being considered for further SI prefixes. Many different websites have different proposals for what comes after yottabyte and they all are different. Nothing should be put on Wikipedia unless there is a consensus, and particularly for this template unless there is something from the SI governing bodies like the BIPM or something. Brian Shaposky (talk) 17:27, 10 May 2021 (UTC)[reply]

Scientific notation[edit]

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)[reply]

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)[reply]

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)[reply]

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)[reply]
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)[reply]

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)[reply]

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


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)[reply]


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)[reply]

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)[reply]
Thanks for the explanation, Ceinturion (talk) 23:50, 20 July 2019 (UTC)[reply]

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)[reply]

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)[reply]
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)[reply]
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)[reply]
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)[reply]

why only p?[edit]

Why make such a fuss about p, and not for m, y or z? Dondervogel 2 (talk) 23:47, 9 May 2021 (UTC)[reply]

Personally I think p is the only one that is counterintuitive. Big y and small y are consistent, both mean 10 to the same power as a multiplier/divider. Same for z. Mega and milli are so widely used that no one would ever confuse if they mean one thousand(th) or one million(th). Also, micro is represented by a greek small m, so in that sense, big M and small greek m both mean the same power of 10 as a multiplier/divider, so it is consistent. I just put the note there to help some people who might just glance at this table and not realize that big p and small p are different powers of ten. Say someone needed to check what big P was for a large measurement, then a couple weeks later, they need a super small measurement, and just assume without checking that small p is the same power of ten of what they checked that big P was a couple weeks back. Only a problem since they are not widely used/common knowledge. The notes just help people remember when they don't have the table in front of them by providing some context and clarifications.
Overall, no super strong feelings about it whether or not the note is there, obviously don't want to much clutter. Brian Shaposky (talk) 02:56, 10 May 2021 (UTC)[reply]
Looks like User:Kbrose decided the note was not worth it. No worries. However, when they reverted the edit, they also cleared some of note 2 which was unrelated, assuming that was unintentional, I went back and fixed that. Brian Shaposky (talk) 16:31, 10 May 2021 (UTC)[reply]
Frankly, I don't see the benefit of any of the notes. The second one is especially puzzling and its meaning is only decipherable, after multiple readings and comparisons by reading the history section of those articles. The first one is not beneficial either, if anyone wants to read details of the history, they can visit the article; here, the year alone is perfectly sufficient. I think I am going to remove them all. kbrose (talk) 17:29, 10 May 2021 (UTC)[reply]
I actually tend to agree with you for note 1. For note 2, no strong feelings, I'm kind of new to editing Wikipedia so you can make that judgement call. Brian Shaposky (talk) 22:47, 10 May 2021 (UTC)[reply]

Etymology of "pico"[edit]

According to the template (and the article Pico-) it originates from the Spanish word "pico". That is possible, but the word means "peak" or "beak", not "small". Could it be that it actually has an Italian origin (piccolo)? Dondervogel 2 (talk) 18:28, 10 May 2021 (UTC)[reply]

If from Spanish at all, it is probably from poquito. Without a reference, it should best be deleted. kbrose (talk) 19:06, 10 May 2021 (UTC)[reply]
Oops, thanks for pointing that out Dondervogel 2, that was just me making a mistake, I only copied the contents of the etymology columns over from the page of each of the prefixes. I'll fix it.
Also, if you look at the Talk:Pico-, someone says they confirmed it was Spanish, not Italian, from the 2006 edition of OED. I don't have access to that to confirm it. But I did just check a bunch of dictionary websites and they all say its spanish, meaning, "peak" or "beak".
As far as the references, I just assumed the references from each prefix page were good enough so I didn't have to put them individually in this table. But I guess you're right, the CPGM 1960 Resolution doesn't actually talk about etymology. Brian Shaposky (talk) 22:48, 10 May 2021 (UTC)[reply]
How do we know those online dictionaries are not just mirroring an error that originated here? There is a third, colloquial meaning of "pico" which is "a little bit". For example "mide 2 metros y pico" means "he is little more than 2 metres tall". Without an RS, the Italian "piccolo" (which means small) seems at least as plausible as the Spanish "pico" (which doesn't, except in this colloquial sense). Dondervogel 2 (talk) 00:11, 11 May 2021 (UTC)[reply]
According to Italian Wikipedia "Il nome deriva secondo alcuni[2] dalla parola italiana piccolo, secondo altri[3] dallo spagnolo pico." In English that means "According to some the name is derived from the Italian piccolo and according to others from the Spanish pico". Dondervogel 2 (talk) 00:18, 11 May 2021 (UTC)[reply]
I found a definition of "pico-". This reads (verbatim): "comb. form denoting a factor of 10-12 (picometre). [Sp. pico beak, peak, little bit]".
Source: The Concise Oxford Dictionary, Eighth Edition (1990).
Dondervogel 2 (talk) 08:32, 11 May 2021 (UTC)[reply]
Nice! Why don't you put that reference on the Pico- page where they talk about etymology, since the references for each word wouldn't really fit on this template? Brian Shaposky (talk) 16:33, 11 May 2021 (UTC)[reply]
Done. Dondervogel 2 (talk) 17:16, 11 May 2021 (UTC)[reply]
@Dondervogel 2: Sure, the OED gives the etymology of the word in terms of all the senses of it in Spanish, but they're all not necessarily relevant. The senses of 'peak' (as in a mountain) and 'beak' (as in a bird) are not quite relevant to the meaning in this case, though I guess the latter could be if one were to consider it in the sense of "just the beak". Analogously, the English word vice can mean 'immoral behaviour' as well as 'substitute', and the sense being implied is clear from context. This seems to be consistent with other sources as well. As for the formality of it, WordReference does not mention the sense of 'a little bit' as informal or colloquial. Getsnoopy (talk) 20:48, 19 January 2022 (UTC)[reply]
I think all 3 meanings mentioned by the COD are relevant here. Regarding (in)formality, I have only heard the "little bit" meaning used in a colloquial sense. That does not prove it is never used formally, but it means such use is rare. Dondervogel 2 (talk) 21:01, 19 January 2022 (UTC)[reply]

Yocto, yotta are latin, not greek[edit]

Reference: Proceedings of the 19th CGPM (1991), page 80. French text: (begin of citation) Les préfixes "zepto" et zetta évoquent le nombre sept, en latin "septem" [...] Les préfixes "yocto" et "yotta" évoquent le nombre huit, en latin "octo" (end of citation) -- Wassermaus (talk) 21:13, 15 February 2022 (UTC)[reply]

That seems pretty clear.--Srleffler (talk) 04:19, 17 February 2022 (UTC)[reply]

Etymology and size of template[edit]

This template has grown rather large for an infobox. I'm thinking that the etymology information unduly inflates it, and would be better covered in the individual articles where it can be explaned better than in a narrow column, with footnotes. I propose to remove it. Comments?--Srleffler (talk) 03:50, 28 September 2022 (UTC)[reply]

"English word" column[edit]

I agree with Srleffler's edit comment that etymology does not belong in this table, but rather in individual articles. I would like to suggest that the "English word" column does not belong in a template such as this for the same reason. All the necessary numeric information is already present. Any comments/objections to removing it? —Quondum 14:55, 8 November 2022 (UTC)[reply]

Done. —Quondum 18:51, 17 December 2022 (UTC)[reply]
After reading two renewable energy articles on the Web in a row haphazardly mixing quadrillions of Btus, trillions of Watts, Terawatt·hours, and petawatts of energy, I came to Wikipedia for help andwas surprised that Wikipedia's page on SI prefixes didn't give the English name for each. So I went Be Bold and added a "Number name (short scale)" column to the SI prefixes page/redirect, then realized I was editing a template (I am confused by the relationships between Metric prefixes#List of SI prefixes, this template, ((Common metric prefixes)), and ((SI multiples))) used on multiple pages. So I saved my improvement as User:Skierpage/SI_prefixes_(infobox), and came here to talk about it. I do object to removing the word/name, it would have been better and more incremental to drop the Long scale column. There are plenty of other Web pages that mix English names and SI units, so the mapping from one to the other is clearly useful. And Wikipedia pages think so too as evidenced by:
  1. en_wiki's Names of large numbers and Names of small numbers pages give the SI prefix, so why doesn't the inverse table provide the numbers' name?
  2. en-wiki pages like picosecond helpfully tell you that it's a trillionth of a second, so why isn't the table of SI prefixes equally helpful?
Bring an "English/number name/word" column back, please. -- Skierpage (talk) 03:25, 15 February 2024 (UTC)[reply]
The template had just gotten too large. Infoboxes should be more targeted. Yes, conversions to number names might be useful for a few readers, but lots of bits of information could be useful; we can't and shouldn't jam everything useful into this one table.
We can't really have just a short scale column and not also a long scale one. --Srleffler (talk) 23:54, 17 February 2024 (UTC)[reply]


While the pattern of zepto/zetta and yocto/yotta may suggest quecto/quetta, all sources that I’ve heard say that it’s actually quecca, as it descends from deca. Thoughts? (I had to remake this because I accidentally out in ronto/ronna without realizing that it’s not rotta) 2A00:23C4:37A4:9D01:D11B:7D92:AE15:218A (talk) 22:29, 14 December 2022 (UTC)[reply]

Quecca was an early suggestion, but quetta was approved. NebY (talk) 22:48, 14 December 2022 (UTC)[reply]
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