Editing Space (punctuation) (section)

===Unit symbols and numbers===
{{main|International System of Units#Lexicographic conventions}}

The [[International System of Units|International System of Units (SI)]] prescribes inserting a space between a number and a [[unit of measurement]] (the space being regarded as an implied multiplication sign) but never between a prefix and a base unit; a space (or a [[multiplication dot]]) should also be used between units in compound units.<ref name='BIPM style'>{{cite book 
|url= https://www.bipm.org/documents/20126/41483022/SI-Brochure-9.pdf/ 
|title= The International System of Units (SI) 
|author= International Bureau of Weights and Measures 
|author-link= International Bureau of Weights and Measures 
|page= 149 
|year= 2019 
|edition= 9th 
|access-date= 2023-01-13 
|archive-date= 2023-01-13 
|archive-url= https://web.archive.org/web/20230113090424/https://www.bipm.org/documents/20126/41483022/SI-Brochure-9.pdf/ 
|url-status= live 
}}.</ref>
{{plainlist|indent=1|
* 5.0&nbsp;cm, ''not'' {{not a typo|5.0cm}} or {{not a typo|5.0 c m}} or {{not a typo|5.0 cms}}
* 45&nbsp;kg, ''not'' {{not a typo|45kg}} or {{not a typo|45 k g}} or {{not a typo|45 kgs}}
* {{not a typo|32&nbsp;°C}}, ''not'' {{not a typo|32°C}} or {{not a typo|32° C}}
* 20&nbsp;kN&nbsp;m or 20&nbsp;kN⋅m, ''not'' {{not a typo|20 kNm}} or {{not a typo|20 k Nm}}
* π/2&nbsp;rad, ''not'' {{not a typo|π/2rad}} or {{not a typo|π / 2 rad}}
* 50&nbsp;%, ''not'' {{not a typo|50%}} or {{not a typo|50 percent}} (Note: % is not an SI unit, and many [[style guide]]s do not follow this recommendation; {{not a typo|50%}} is used as adjective, e.g. to express concentration as in 50% acetic acid.)
}}
The only exception to this rule is the traditional symbolic notation of [[angle]]s: [[degree (angle)|degree]] (e.g., 30°), [[minute of arc]] (e.g., 22′), and [[second of arc]] (e.g., 8″).

The SI also prescribes the use of a space<ref>{{Cite book|url=https://www.bipm.org/utils/common/pdf/si-brochure/SI-Brochure-9.pdf|title=The International System of Units|edition=9th|publisher=International Bureau of Weights and Measures|year=2019|isbn=978-92-822-2272-0|pages=150|access-date=2019-11-13|archive-date=2021-10-18|archive-url=https://web.archive.org/web/20211018184555/https://www.bipm.org/documents/20126/41483022/SI-Brochure-9.pdf/fcf090b2-04e6-88cc-1149-c3e029ad8232|url-status=live}}</ref> (often typographically a [[thin space]]) as a [[thousands separator]] where required. Both the point and the comma are reserved as [[decimal marker]]s.
{{plainlist|indent=1|
* 1 000 000 000 000 (thin space) or 1000000 ''not'' 1,000,000 or 1.000.000
* 1 000 000 000 000 (regular space which is significantly wider)
}}
{{anchor|Non-breaking space}}Sometimes a [[Non-breaking space#Width variation|narrow non-breaking space]] or [[non-breaking space]], respectively, is recommended (as in, for example, [[IEEE Standards]]<ref>{{Cite web|url=https://standards.ieee.org/wp-content/uploads/import/governance/revcom/scc14.pdf|title=SCC 14 Conventions for Metrication of IEEE Standards|date=2017-10-31|publisher=[[IEEE]]|access-date=2019-11-12|archive-date=2019-07-23|archive-url=https://web.archive.org/web/20190723192955/https://standards.ieee.org/content/dam/ieee-standards/standards/web/governance/revcom/scc14.pdf|url-status=live}}</ref> and [[IEC standards]]<ref>{{Cite web |date=2022-07-18 |title=Writing and formatting {{!}} IEC |url=https://www.iec.ch/standards-development/writing-and-formatting#article-header-id-65fd-usingnon-breakingspacestokeeptextelementstogether |url-status=live |archive-url=https://web.archive.org/web/20220718143708/https://www.iec.ch/standards-development/writing-and-formatting |archive-date=2022-07-18 |access-date=2022-07-18 |website=International Electrotechnical Commission}}</ref>) to avoid the separation of units and values or parts of compounds units, due to automatic [[line wrap and word wrap]].