International System of Units was one of the Natural sciences good articles, but it has been removed from the list. There are suggestions below for improving the article to meet the good article criteria. Once these issues have been addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.
Article milestones Date Process Result July 27, 2013 Peer review Reviewed September 12, 2013 Good article nominee Not listed November 22, 2013 Good article nominee Listed December 4, 2023 Good article reassessment Delisted Current status: Delisted good article

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Archives (mm/yyyy)

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I propose to replace in the article History of the metre the four sections Universal measure, Meridional definition, Mètre des Archives and International prototype metre by the recently suppressed subsections in the article Metre, section History of definition:

Universal measure: the metre linked to the figure of the Earth,

the introductory paragraph of the section Metrology and paradigm shift in physics and

the text of the subsection Wavelength definition up to Albert Michelson soon took up the idea and improved it.

Alternatively an article named for example Errors in sciences and Internationalisation of the metre could be created.

Charles Inigo (talk) 13:13, 26 January 2025 (UTC)[reply]

Feel free to create Draft:Errors in sciences and Internationalisation of the metre so that everybody can have a clear view of what you have in mind. fgnievinski (talk) 17:07, 26 January 2025 (UTC)[reply]

I rather propose the article History of the metre should beginn with the sections which have recently been removed from the article Metre.

You can consult the old (12:24, 25 January 2025) version of the article Metre of which a link is provided below in order to have a clear view of what I have in mind :

From Universal measure: the metre linked to the figure of the Earth up to "Charles Sanders Peirce's work promoted the advent of American science at the forefront of global metrology. Alongside his intercomparisons of artifacts of the metre and contributions to gravimetry through improvement of reversible pendulum, Peirce was the first to tie experimentally the metre to the wave length of a spectral line. According to him the standard length might be compared with that of a wave of light identified by a line in the solar spectrum. Albert Michelson soon took up the idea and improved it". Charles Inigo (talk) 06:51, 27 January 2025 (UTC)[reply]

The content of History of the metre should not be discussed here. Johnjbarton (talk) 17:56, 27 January 2025 (UTC)[reply]

The redirect SI has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2024 November 13 § SI until a consensus is reached. BD2412 T 21:08, 13 November 2024 (UTC)[reply]

 Done the result was keep Johnjbarton (talk) 17:56, 27 January 2025 (UTC)[reply]

Why o why are the colours in such a weird order ? Why not just stick with the order of the colours in the rainbow. The use of the colour yellow for seconds screams off the page as an anomaly. Who in their right mind would put yellow next to red and then orange next to green. Please, please can someone recolour this graphic so it is not so offensive. Thank you ! 46.208.209.96 (talk) 08:30, 2 April 2025 (UTC)[reply]

"Who in their right mind" is the International Bureau of Weights and Measures, from whom the image was obtained.

You have not explained why you consider having certain colours adjacent is so "offensive". The only improvement might be to invert the text colour for any segment whose colouring currently contravenes MOS:CONTRAST. Bazza 7 (talk) 09:02, 2 April 2025 (UTC)[reply]

This seems to be an old version of the SI circle. The correct circle (with colours in rainbow order) can be found at https://www.bipm.org/en/measurement-units/si-promotion. I suggest changing it. /Tobias 192.71.100.250 (talk) 09:20, 19 May 2025 (UTC)[reply]

Please provide your opinion at Litre. Dondervogel 2 (talk) 16:40, 11 May 2025 (UTC)[reply]

No, it isn't. DOI:10.59161/AUEZ1291 chapter 4. -- Wassermaus (talk) 00:52, 30 December 2025 (UTC)[reply]

@Wassermaus: Please reply on the Litre talk page. Dondervogel 2 (talk) 08:45, 30 December 2025 (UTC)[reply]

I don't get the formula for 1 Kg to work, computing the expression on the right side of the equal sign gives you 1/Kg, so how that can equal 1 Kg beats me. Planck's constant is Js and when you multiply that with the hyperfine transision frequency which is Hz you get J which is kg times (m/s) squared and if you then divide that by the speed of light squared you get Kg. The equation has numerator and denominator switched I think. 178.174.125.168 (talk) 19:06, 30 May 2025 (UTC)[reply]

Most of what you say is correct, up to "you get kg". And kg is what you want, so the numerator and denominator are the right way round. However the formula would be much easier to follow if it were developed as a product of its three constituent ratios.---Ehrenkater (talk) 19:16, 30 May 2025 (UTC)[reply]

Quantum logic clocks lead the candidates for a future redefinition of the second. The NIST ²⁷Al⁺ quantum logic clock's transition frequency, as of April 2025, is 1 121 015 393 207 859.16(18) Hz relative to the current SI second.EdPeggJr (talk) 03:00, 15 July 2025 (UTC)[reply]

in my last edit, you'll see that most of its changes are (symbol: (blank), (what it measures)), i think they could be shortened into efn as they dont seem essential Misterpotatoman (talk) 08:38, 26 December 2025 (UTC)[reply]

I don't think this sentence needs to be shorter: the seven units are central to the topic. Please don't use efn in any introduction. Details don't belong in introductions at all. Johnjbarton (talk) 16:20, 26 December 2025 (UTC)[reply]

Per MOS:RETAIN "When an English variety's consistent usage has been established in an article, maintain it in the absence of consensus to the contrary." This article was marked as having a specific spelling selected by consensus. In my view this rule exists to avoid frivolous changes back and forth, which is what we have now. @Dondervogel 2 @Misterpotatoman. Johnjbarton (talk) 18:43, 26 December 2025 (UTC)[reply]

Fair point about spelling, though I still maintain there were other improvements involved. I would add that there is one reason to prefer "-ize" in this article, which is that international standards (at least by ISO, IEC and BIPM) use that spelling. Dondervogel 2 (talk) 19:49, 26 December 2025 (UTC)[reply]

If the official documentation uses a spelling I think that makes a strong case for us to use that spelling if we could create a consensus to do so. Like I said, in my opinion the purpose of the rule is to avoid back and forth. Shall we try?

The template was added in 2012. It seems like the spelling was established in 2008 during this discussion: Talk:International_System_of_Units/Archives/12/2008#WP:ENGVAR. As far as I can tell the official documentation was not consulted. Johnjbarton (talk) 20:12, 26 December 2025 (UTC)[reply]

Yes, let's try to establish a consensus for one form of spelling or the other (-ise vs -ize) and then implement that spelling. I would not object to you (or anyone else) restoring "-ise" while the matter is discussed. I'd offer to do that myself if it were not such a pain separating those changes from the others made by Misterpotatoman with the same edit. (To be clear, I am not arguing for US spelling, but for UK spelling with the OED-sanctioned "-ize" variant) Dondervogel 2 (talk) 21:51, 26 December 2025 (UTC)[reply]

The current article uses British English per a Talk:International_System_of_Units/Archives/12/2008#WP:ENGVAR discussion in 2008. The authoritative document for the SI system is

• International Bureau of Weights and Measures (December 2022), The International System of Units (SI) (PDF), vol. 2 (9th ed.), ISBN 978-92-822-2272-0

which appears to use spellings consistent with the Oxford English Dictionary, matching the Manual of Style British English with "-ize" (Oxford spelling). The manual uses "standardization", "capitalized", "recognized", "realizations", "idealized", but "centre" and "advised" all consistent with our Oxford spelling. By adopting this Oxford variant of British spelling we slightly improve our ability to verify our content against the standard. I estimate that adopting Oxford spelling would change 13 words in the current version.

I propose to adopt Oxford spelling in this article. Johnjbarton (talk) 23:59, 26 December 2025 (UTC)[reply]

According to the ISO House Style

ISO documents use Oxford English spelling, which is British spelling in combination with the suffix ‑ize (rather than ‑ise) for about 200 verbs that generally originate from the Greek -izo suffix, e.g. organize, standardize. For other words, use an “s”, e.g. analyse, paralyse. In case of doubt, follow the spelling of the Oxford English Dictionary.

Dondervogel 2 (talk) 00:16, 27 December 2025 (UTC)[reply]

@Dondervogel 2, why should we should ignore Wikipedia policies and guidelines and follow the policy and guidelines of the ISO organisation for this particular article? -- DeFacto (talk). 14:42, 27 December 2025 (UTC)[reply]

• The proposal is not to follow ISO spelling, but to follow the spelling of international English, which happens to be used by the UN, ISO, IEC and BIPM. I don't see why use of international spelling should be controversial for an article about the International System of Units.
• What aspect of the proposal contravenes Wikipedia policies or guidelines?

Dondervogel 2 (talk) 21:30, 27 December 2025 (UTC)[reply]

There isn't a single international English in Wikipedia, there is a multitude of variants and guidelines for which to use. -- DeFacto (talk). 21:36, 27 December 2025 (UTC)[reply]

I am referring to the international spelling used by the UN, ISO, IEC and BIPM. This is a perfectly legitimate variant of the English spelling, adopted by the United Nations and (unless you can demonstrate otherwise), completely compatible by Wikipedia guidelines. Dondervogel 2 (talk) 21:41, 27 December 2025 (UTC)[reply]

British Oxford English is not 'international spelling' it is British English but basically using 'ize' instead of 'ise', which some organisations have chosen for their publications, so that is not a valid reason for changing this article to it. -- DeFacto (talk). 22:01, 27 December 2025 (UTC)[reply]

While "Brtish English with '-ize'" seems a fair description of Oxford English, I see it as a standard international form of English because it is used by a major international organisations such as ISO, NATO, and the UN. The fact that all these organisations have adopted Oxford English seems to me like a good reason to adopt Oxford English for International System of Units. My point is summed up by Which spelling standard in English? 'Oxford spelling'

'Oxford spelling' is used by the principal and most prestigious English dictionaries such as the Oxford English Dictionary, the Collins English Dictionary and the Cambridge dictionaries, as well as by prestigious publishers and publications and a host of international organizations, such as Oxford University Press, Cambridge University Press, Penguin, the Encyclopaedia Britannica, Nature, the United Nations and all of the bodies that report to it (such as the World Health Organization, the International Labour Organization, UNICEF and UNESCO), the World Trade Organization, the International Organization for Standardization (ISO), the International Atomic Energy Agency (IAEA), the Organization of the Petroleum Exporting Countries (OPEC), Interpol, the International Committee of the Red Cross, World Wide Fund for Nature (WWF), Amnesty International, the World Economic Forum and NATO, among others.

Dondervogel 2 (talk) 14:19, 28 December 2025 (UTC)[reply]

However, Wikipedia, a massive global publisher of English language works, does not recommend British Oxford English over any other variety of English, so that is clearly not a valid reason for changing the article to use it (per MOS:RETAIN) so we should stick with the status quo. -- DeFacto (talk). 15:14, 28 December 2025 (UTC)[reply]

The IEC House Style states

Use “z” instead of “s” in words ending in ize, ization

and provides the examples "organization, organize, standardization, standardize, optimization, optimize, harmonization, harmonize, emphasize, recognize, urbanize" Dondervogel 2 (talk) 11:49, 27 December 2025 (UTC)[reply]

@Dondervogel 2, who is IEC, and why do you think we should abandon Wikipedia's own policies and guidelines in favour of those of IEC? -- DeFacto (talk). 14:56, 27 December 2025 (UTC)[reply]

(I added a sub-heading to clarify the meaning of IEC)

• The proposal is not to follow IEC spelling, but to follow the spelling of international English, which happens to be used by the UN, ISO, IEC and BIPM. I don't see why use of international spelling should be controversial for an article about the International System of Units.
• What aspect of the proposal contravenes Wikipedia policies or guidelines?

Dondervogel 2 (talk) 21:32, 27 December 2025 (UTC)[reply]

So why did you introduce a section about the IEC? See my reply in ISO for my the response to the identical questions there. -- DeFacto (talk). 21:40, 27 December 2025 (UTC)[reply]

• Because the IEC follows the same international spelling rules as the other organisations I mentioned (UN, ISO and BIPM).
• See my reply under the ISO heading.

Dondervogel 2 (talk) 21:44, 27 December 2025 (UTC)[reply]

The United Nations also uses Oxford English spelling. Dondervogel 2 (talk) 11:58, 27 December 2025 (UTC)[reply]

Support (please reply to the topic post with a clear stand, thanks). Johnjbarton (talk) 00:00, 27 December 2025 (UTC)[reply]

Support per proposal, supported by ISO house style. Dondervogel 2 (talk) 00:19, 27 December 2025 (UTC)[reply]

Please elaborate, how does that document relate to the style used in a Wikipedia article (as opposed to ISO document) and which specific section of it are you referring to? Jähmefyysikko (talk) 11:39, 27 December 2025 (UTC)[reply]

• My interpretation of the proposal is to follow the spelling of international English, which happens to be used by ISO (hence the relevance of the ISO House Style). I have since added relevant statements about IEC and UN spelling guides, which are fully consistent withISO.
• I am referring to the part that reads "ISO documents use Oxford English spelling, which is British spelling in combination with the suffix ‑ize (rather than ‑ise) for about 200 verbs that generally originate from the Greek -izo suffix, e.g. organize, standardize. For other words, use an “s”, e.g. analyse, paralyse. In case of doubt, follow the spelling of the Oxford English Dictionary."

Dondervogel 2 (talk) 21:37, 27 December 2025 (UTC)[reply]

Speaking for myself, the SI system is described using words almost but not quite the same as the words we use. With a minor change to our article on the SI system, we would use the same words. That spelling matches one of our English variants. That's it. Seems obvious to me we should do this, just like we would update the article to in other ways rather than keep is in state it was written 17 years ago. Johnjbarton (talk) 23:24, 27 December 2025 (UTC)[reply]

Oppose because it's a frivolous change. This is a former Good Article, surely getting it back to that status is where energy should be spent. Tercer (talk) 10:36, 27 December 2025 (UTC)[reply]

Switching arbitrarily between equally legitimate variants (eg UK and US) would be frivolous. There is nothing frivolous about arguing for international spelling in an article about the International System of Units. Dondervogel 2 (talk) 21:50, 27 December 2025 (UTC)[reply]

"standardization" and "standardisation" are equally legitimate, and neither is "international spelling", whatever that means. Tercer (talk) 16:10, 28 December 2025 (UTC)[reply]

Oxford English is considered international English by many, including the United Nations.

You are entitled to your opinion. The United Nations

The online Oxford Dictionary (https://premium.oxforddictionaries.com/english/ (set to British English) is the current authority for spelling in the United Nations. If more than one spelling is given in the dictionary, use the form listed first unless otherwise indicated below. The Concise Oxford English Dictionary, twelfth edition, is an acceptable alternative.

and the University of Pompeu Fabra

The English language, which is spoken either as a first or a second language in many countries throughout the world, basically has three main orthographic standards: the British, the American and 'Oxford spelling', which is similar to the British standard but with a few nuances and can be considered the most international English (world English, according to the Oxford English Dictionary) and also, to a certain extent, the most neutral in that it does not coincide fully with the official standard used by any English-speaking government.

are entitled to theirs. Dondervogel 2 (talk) 06:12, 29 December 2025 (UTC)[reply]

Oppose per MOS:RETAIN which says There is only very exceptionally (such as when a topic has strong national ties, or the change reduces ambiguity) a valid reason for changing from one acceptable option to another. And I do not think that the fact that the house style of one of the sources used for the article uses a different variety of English than our article is a sufficiently compelling reason to change our variety which has been used for 17+ years. -- DeFacto (talk). 14:38, 27 December 2025 (UTC)[reply]

The first sentence of MOS:RETAIN is "When an English variety's consistent usage has been established in an article, maintain it in the absence of consensus to the contrary." We have maintained it to this point and we are not seeking a "consensus to the the contrary". This is a minor change to make our page consistent with the standard which it describes. As far as I can tell the discussion back in 2008 did not consider this aspect. This change is not really not a big deal. Johnjbarton (talk) 23:18, 27 December 2025 (UTC)[reply]

• Oppose this proposal that British spelling with -ise shouldn't be used for international subjects. Oppose also any suggestion that we should use spelling that (selected) sources use; we went through a bad phase of editors arguing whether we should use the units that selected sources use, and we don't want to do it again over spelling. If new principles restricting the use of -ise or requiring source-based spelling are to be followed, they need to be agreed at Wikipedia talk:Manual of Style/Spelling. NebY (talk) 16:58, 28 December 2025 (UTC)[reply]

  @NebY: I fully agree we should not follow sources. That path leads to chaos and defeats the object of a MoS. Is your advice to move this discussion to the MoS/spelling talk page? Dondervogel 2 (talk) 20:39, 28 December 2025 (UTC)[reply]

• Oppose. The proposal runs counter to the spirit (though not the letter) of WP:RETAIN. That guideline was designed to prevent wasting time in unnecessary switching between English spelling varieties. In constrast to the organizations like ISO/IEC and UN, Wikipedia has not adopted a uniform spelling. Jähmefyysikko (talk) 06:43, 29 December 2025 (UTC)[reply]

[[1]] this graphic is quite appropriate but is old and could use improvement, and perhaps someone could add MOMENTUM to the diagram? Lee De Cola (talk) 22:28, 29 December 2025 (UTC)[reply]