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{{Short description|Numerical symbol}}
{{For|the Wikipedia guideline|MOS:DECIMAL|selfref=true}}
{{use dmy dates|date=November 2022}}
{{Redirect|Decimal period|the period of a repeating decimal fraction|Repeating decimal}}

{{Numeral systems}}
[[File:Common_decimal_separators_-_Decimal_point_and_decimal_comma.png|thumb|right|Both a [[comma]] and a [[full stop|period]] (or full-stop) are generally accepted decimal separators for international use.]]
[[File:Thousands separators.gif|thumb|Three ways to group the number ten thousand with digit group separators.<br/>1) Space, the internationally recommended thousands separator.<br/>2) Period (or full stop), the thousands separator used in many non-English speaking countries.<br/>3) Comma, the thousands separator used in most English-speaking countries.]]

A '''decimal separator''' is a symbol that separates the [[integer]] part from the [[fractional part]] of a [[number]] written in [[decimal]] form (e.g., "." in ''12.45''). Different countries officially designate different symbols for use as the separator. The choice of symbol also affects the choice of symbol for the [[thousands separator]] used in digit grouping.

Any such symbol can be called a '''decimal mark''', '''decimal marker''', or '''decimal sign'''. Symbol-specific names are also used; '''decimal point''' and '''decimal comma''' refer to a dot (either [[Baseline dot|baseline]] or [[Middle dot|middle]]) and [[comma]] respectively, when it is used as a decimal separator; these are the usual terms used in English,<ref>{{cite web|url=https://www.collinsdictionary.com/dictionary/english/decimal-point|title=Decimal point definition and meaning {{!}} Collins English Dictionary|website=www.collinsdictionary.com|language=en|access-date=2018-07-05}}</ref><ref name=":0">{{Cite web|last=Weisstein|first=Eric W.|title=Decimal Point|url=https://mathworld.wolfram.com/DecimalPoint.html|access-date=2020-08-22|website=mathworld.wolfram.com|language=en}}</ref><ref>{{cite web|url=https://dictionary.cambridge.org/dictionary/english/decimal-point|title=decimal point Meaning in the Cambridge English Dictionary|website=dictionary.cambridge.org|language=en|access-date=2018-07-05}}</ref> with the aforementioned generic terms reserved for abstract usage.<ref>{{Cite news|url=https://www.howtogeek.com/245510/how-to-change-excels-decimal-separators-from-periods-to-commas/|title=How to Change Excel's Decimal Separators from Periods to Commas|access-date=2018-07-05|language=en-US}}</ref><ref>{{Cite news|url=https://www.smartickmethod.com/blog/math/learning-resources/decimal-separators/|title=Decimal Separators: Points or commas? - Elementary Math|date=2018-01-19|work=Elementary Math|access-date=2018-07-05|language=en}}</ref>

In many contexts, when a number is spoken, the function of the separator is assumed by the spoken name of the symbol: ''comma'' or ''point'' in most cases.<ref>{{Cite web|title=Definition of Decimal Point|url=https://www.mathsisfun.com/definitions/decimal-point.html|access-date=2020-08-22|website=www.mathsisfun.com}}</ref><ref name=":0" /><ref>{{Cite news|url=https://www.grammarphobia.com/blog/2012/02/decimal-point.html|title=Mythematics: a decimal point|date=2012-02-17|work=Grammarphobia|access-date=2018-07-05|language=en-US}}</ref> In some specialized contexts, the word ''decimal'' is instead used for this purpose (such as in [[International Civil Aviation Organization]]-regulated [[air traffic control]] communications). In mathematics, the decimal separator is a type of [[#Radix point|radix point]], a term that also applies to number systems with bases other than ten.

==History==
===Hellenistic–Renaissance eras===
{{anchor|Separatrix|Pythagorean arc}}
In the [[Middle Ages]], before printing, a [[overline|bar]] ( ¯ ) over the [[units digit]] was used to separate the integral part of a number from its [[fractional part]], as in 9{{overline|9}}95 (meaning 99.95 in [[decimal]] point format). A similar notation remains in common use as an underbar to superscript digits, especially for monetary values without a decimal separator, as in 99<sup>{{underline|95}}</sup>. Later, a "separatrix" (i.e., a short, roughly vertical ink stroke) between the units and tenths position became the norm among [[Mathematics in medieval Islam|Arab mathematicians]] (e.g. 99'''ˌ'''95), while an L-shaped or [[vertical bar]] ({{!}}) served as the separatrix in England.<ref>{{cite dictionary |dictionary=Oxford English Dictionary |title=separatrix, ''n.'' |place=Oxford, UK |publisher=Oxford University Press }}</ref> When this character was [[typeset]], it was convenient to use the existing [[Comma (punctuation)|comma]] (99''','''95) or [[full stop]] (99'''.'''95) instead.

Positional [[decimal fraction]]s appear for the first time in a book by the Arab mathematician [[Abu'l-Hasan al-Uqlidisi]] written in the 10th century.<ref name=Berggren>{{cite book |first=J. Lennart |last=Berggren |year=2007 |chapter=Mathematics in Medieval Islam |editor-first=Victor J. |editor-last=Katz |title=The Mathematics of Egypt, Mesopotamia, China, India, and Islam: A sourcebook |publisher=Princeton University Press |isbn=978-0-691-11485-9 |page=530 }}</ref> The practice is ultimately derived from the decimal [[Hindu–Arabic numeral system]] used in [[Indian mathematics]],<ref>{{cite book |author1=Reimer, L. |author2=Reimer, W. |title=Mathematicians are People, too: Stories from the lives of great mathematicians |volume=2 |year=1995 |pages=22 |place=Parsippany, NJ |publisher=Pearson Education, / Dale Seymor Publications |isbn=0-86651-823-1}}</ref> and popularized by the [[Persian people|Persian]] mathematician [[Al-Khwarizmi]],<ref>{{cite web |url=http://www.oxfordislamicstudies.com/article/opr/t125/e1305 |archive-url=https://web.archive.org/web/20130618081123/http://www.oxfordislamicstudies.com/article/opr/t125/e1305 |url-status=dead |archive-date=18 June 2013 |title=Khwarizmi, Abu Jafar Muhammad ibn Musa al- |type=biography |website=Oxford Islamic Studies Online}}</ref> when [[Latin]] translation of [[#Arithmetic|his work]] on the [[Indian numerals]] introduced the decimal [[Positional notation|positional number system]] to the Western world. His ''[[Compendious Book on Calculation by Completion and Balancing]]'' presented the first systematic solution of [[linear equation|linear]] and [[quadratic equation]]s in Arabic.

[[Pope Sylvester II|Gerbert of Aurillac]] marked triples of columns with an arc (called a "Pythagorean arc"), when using his Hindu–Arabic numeral-based abacus in the 10th&nbsp;century. [[Fibonacci]] followed this convention when writing numbers, such as in his influential work {{lang|la|[[Liber Abaci]]}} in the 13th&nbsp;century.<ref>{{cite book |last=Devlin |first=Keith |year=2011 |title=The Man of Numbers: Fibonacci's Arithmetic Revolution |publisher=Walker & Company |place=New York, NY |isbn=9780802779083 |pages=[https://archive.org/details/manofnumbersfibo0000devl/page/44 44–45] |url=https://archive.org/details/manofnumbersfibo0000devl |url-access=registration }}</ref> 

The earliest known record of using the decimal point is in the astronomical tables compiled by the Italian merchant and mathematician [[Giovanni Bianchini]] in the 1440s.<ref>{{Cite journal |last=Marchant |first=Jo |date=2024-02-19 |title=The decimal point is 150 years older than historians thought |url=https://www.nature.com/articles/d41586-024-00473-2 |journal=Nature |language=en |doi=10.1038/d41586-024-00473-2}}</ref>{{contradict-inline|History of mathematical notation#Indian and Arabic numerals and notation}}

Tables of [[logarithm]]s prepared by [[John Napier]] in 1614 and 1619 used the period (full stop) as the decimal separator, which was then adopted by [[Henry Briggs (mathematician)|Henry Briggs]] in his influential 17th century work.

In [[France]], the full stop was already in use in printing to make [[Roman numerals]] more readable, so the comma was chosen.<ref name=Santillana-1996>{{cite encyclopedia |encyclopedia=Enciclopedia Universal Santillana |year=1996 |publisher=Santillana S.A. |place=Barcelona, Spain |isbn=84-294-5129-3 |title=Comma |at=def.&nbsp;2 |quote=coma: MAT. Signo utilizado en los números no enteros para separar la parte entera de la parte decimal o fraccionaria; p.&nbsp;ej., {{nobr| 2,123 .}} }}</ref>

Many other countries, such as Italy, also chose to use the comma to mark the decimal units position.<ref name=Santillana-1996/> It has been [[ISO 80000-2|made standard]] by the [[International Organization for Standardization|ISO]] for international blueprints.<ref>{{cite report |title=Quantities and units |section=Part&nbsp;2: Mathematical signs and symbols to be used in the natural sciences and technology |id=ISO 80000-2:2009 |year=2009 |publisher=[[International Organization for Standardization]] |section-url=http://www.iso.org/iso/catalogue_detail?csnumber=31887 |access-date=1 July 2010}}</ref> However, English-speaking countries took the comma to separate sequences of three digits. In some countries, a raised dot or dash (''{{visible anchor|upper comma}}'') may be used for grouping or decimal separator; this is particularly common in handwriting.

===English-speaking countries===
In the [[United States]], the full stop or period (.) is used as the standard decimal separator.

[[File:Interpunct as decimal point in Henderson 1839.png|thumb|upright=1.8|The [[interpunct]] (·) used as a decimal separator in a British print from 1839<ref>for example: {{cite journal |author=Henderson, Thomas |date=1839-01-03 |title=On the parallax of {{mvar|α}}&nbsp;Centauri |journal=[[Memoirs of the Royal Astronomical Society]] |volume=11 |pages=61–64, esp.&nbsp;64 |bibcode=1840MmRAS..11...61H |via=scan published by [[Harvard-Smithsonian Center for Astrophysics]] }}</ref>]]
In the nations of the [[British Empire]] (and, later, the [[Commonwealth of Nations]]), the full stop could be used in typewritten material and its use was not banned, although the [[interpunct]] (a.k.a. decimal point, point or mid dot) was preferred as a decimal separator, in printing technologies that could accommodate it, e.g. {{nobr| 99·95 .}}<ref>{{cite book |author1=Reimer, L. |author2=Reimer, W. |year=1990 |title=Mathematicians are People, too: Stories from the lives of great mathematicians |volume=1 |page=41 |place=Parsippany, NJ |publisher=Pearson Education / Dale Seymor Publications |isbn=0-86651-509-7}}</ref> However, as the mid dot was already in common use in the mathematics world to indicate multiplication, the [[SI]] rejected its use as the decimal separator.

During the beginning of British [[metrication]] in the late 1960s and with impending currency [[decimalisation]], there was some debate in the United Kingdom as to whether the decimal comma or decimal point should be preferred: the [[British Standards Institution]] and some sectors of industry advocated the comma and the [[Decimal Day|Decimal Currency Board]] advocated for the point. In the event, the point was chosen by the [[Ministry of Technology]] in 1968.<ref>{{cite journal | title = Victory on points | year = 1968 | journal = Nature | volume = 218 | issue = 5137 | page = 111 | bibcode = 1968Natur.218S.111. | doi = 10.1038/218111c0 | doi-access = free}}</ref>

[[File:MUTCD-CA G11-6.svg|thumb|right|upright|x180px|California milepost marker at mile 144.44]]
When South Africa [[metrication|adopted the metric system]], it adopted the comma as its decimal separator,<ref>{{cite periodical |title=Government Notice R.&nbsp;1144 |periodical=Government Gazette |issue=4326 |date=5 July 1974 |page=55 |url=https://laws.parliament.na/cms_documents/gg-4326-a7726e51e7.pdf|archive-url=https://web.archive.org/web/20210308203659/https://laws.parliament.na/cms_documents/gg-4326-a7726e51e7.pdf |archive-date=8 March 2021 }}</ref> although a number of house styles, including some English-language newspapers such as ''[[Sunday Times (South Africa)|The Sunday Times]]'', continue to use the full stop.{{citation needed|date=January 2015}}

Previously, signs along [[California]] roads expressed distances in decimal numbers with the decimal part in superscript, as in 3<sup><u>7</u></sup>, meaning 3.7&nbsp;.{{cn|date=November 2024}} Though California has since transitioned to [[mixed number]]s with [[common fraction]]s, the older style remains on [[California postmile|postmile]] markers and bridge inventory markers.

===Constructed languages===
The three most spoken [[international auxiliary language]]s, [[Ido]], [[Esperanto]], and [[Interlingua]], all use the comma as the decimal separator.

Interlingua has used the comma as its decimal separator since the publication of the [[Interlingua: A Grammar of the International Language|Interlingua Grammar]] in 1951.<ref>{{cite web |series=Grammar of Interlingua |title=Parts of Speech – Numerals |url=http://members.optus.net/~ado_hall/interlingua/gi/parts_of_speech/numerals.html |access-date=2008-03-18 |url-status=dead |archive-url=http://arquivo.pt/wayback/20160516201404/http://members.optus.net/~ado_hall/interlingua/gi/parts_of_speech/numerals.html |archive-date=2016-05-16}}</ref>

Esperanto also uses the comma as its official decimal separator, while thousands are usually separated by [[non-breaking space]]s (e.g. {{nobr|12 345 678,9}}). It is possible to separate thousands by a [[full stop]] (e.g. {{nobr|12.345.678,9}}), though this is not as common.<ref>{{cite book |last1=Wennergren |first1=Bertilo |title=Plena Manlibro de Esperanta Gramatiko |trans-title=Complete Manual of Esperanto Grammar |chapter=Helposignoj |trans-chapter=Helping Symbols |edition=15.4 |url=https://bertilow.com/pmeg/ |chapter-url=https://bertilow.com/pmeg/skribo_elparolo/skribo/helposignoj.html |date=5 July 2023 |lang=Esperanto}}</ref>

Ido's ''Kompleta Gramatiko Detaloza di la Linguo Internaciona Ido'' (Complete Detailed Grammar of the International Language Ido) officially states that commas are used for the decimal separator while full stops are used to separate thousands, millions, etc. So the number 12,345,678.90123 (in American notation) for instance, would be written ''12.345.678,90123'' in Ido.

The 1931 grammar of [[Volapük]] uses the comma as its decimal separator, and – somewhat unusually – uses the middle dot as the thousands separator (12·345·678,90123).<ref>{{cite book |author=de&nbsp;Jong, Arie |author-link=Arie de Jong |year=2012 |title=Gramat Volapüka. Cathair na Mart |editor=Everson, Michael |publisher=Evertype |isbn=978-1-904808-94-7 |url=http://evertype.com/books/dejong-gramat.html}}</ref>

In 1958, disputes between European and American delegates over the correct representation of the decimal separator nearly stalled the development of the [[ALGOL]] computer programming language.<ref>Perlis, Alan, ''The American Side of the Development of ALGOL'', ACM SIGPLAN Notices, August 1978.</ref> ALGOL ended up allowing different decimal separators, but most computer languages and standard data formats (e.g., [[C (programming language)|C]], [[Java (programming language)|Java]], [[Fortran]], [[CSS|Cascading Style Sheets (CSS)]]) specify a dot. C and a couple of others permit a quote (') as thousands separator, and many others like Python and Julia, (only) allow `_` as such a separator (it's usually ignored, i.e. also allows 1_00_00_000 aligning with the Indian number style of 1,00,00,000 that would be 10,000,000 in the US).

=== Radix point ===
In [[mathematics]] and [[computing]], a '''radix point''' or '''radix character''' is a symbol used in the display of numbers to separate the [[integer]] part of the value from its [[fractional part]]. In [[English language|English]] and many other languages (including many that are written right-to-left), the integer part is at the left of the radix point, and the fraction part at the right of it.<ref>{{cite book |last1=Van Verth |first1=James M. |last2=Bishop |first2=Lars M. |year=2008 |title=Essential Mathematics for Games and Interactive Applications: A programmers' guide |edition=2nd |place=Boca Raton, FL |publisher=CRC Press |page=7 |isbn=9780123742971 |url=https://books.google.com/books?id=zkEY9RIm4WkC&pg=PA7}}</ref>

A radix point is most often used in [[decimal]] (base 10) notation, when it is more commonly called the [[decimal point]] (the prefix [[wiktionary:deci-|deci-]] implying [[base 10 number system|base&nbsp;10]]). In [[List of countries where English is an official language|English-speaking countries]], the decimal point is usually a small dot (.) placed either on the baseline, or halfway between the baseline and the top of the [[Numerical digit|digits]] ('''·''')<ref name=oracle>{{cite report |title=International Language Environments Guide |url=https://docs.oracle.com/cd/E19455-01/806-0169/overview-9/index.html |archive-url=https://web.archive.org/web/20120115042427/https://docs.oracle.com/cd/E19455-01/806-0169/overview-9/index.html|archive-date=2012-01-15 |access-date=2018-12-19 |website=[[Oracle Corporation|Oracle Corporation Docs]] |df=dmy-all}}</ref>{{efn|name=oracle_quote|Great Britain and the United States are two of the few places in the world that use a period to indicate the decimal place. Many other countries use a comma instead. The decimal separator is also called the ''radix'' character. Likewise, while the U.K. and U.S. use a comma to separate groups of thousands, many other countries use a period instead...<ref name=oracle/>}}
In many other countries, the radix point is a comma (,) placed on the baseline.<ref name=oracle/>{{efn|name=oracle_quote}}

These conventions are generally used both in machine displays ([[printing]], [[computer monitor]]s) and in [[handwriting]]. It is important to know which notation is being used when working in different software programs. The respective [[ISO 31-0#Numbers|ISO standard]] defines both the comma and the small dot as decimal markers, but does not explicitly define universal radix marks for bases other than 10.

Fractional numbers are rarely displayed in other [[Radix|number bases]], but, when they are, a radix character may be used for the same purpose. When used with the [[Binary number|binary]] ([[Binary number|base&nbsp;2]]) representation, it may be called "binary point".

==Current standards==
The 22nd [[General Conference on Weights and Measures]]<ref name=CGPM-22nd-R10/> declared in 2003 that "the symbol for the decimal marker shall be either the point on the line or the comma on the line". It further reaffirmed that
: "numbers may be divided in groups of three in order to facilitate reading; neither dots nor commas are ever inserted in the spaces between groups"<ref name=CGPM-22nd-R10>
{{cite conference
 |title=Resolution&nbsp;10
 |conference=22nd [[General Conference on Weights and Measures]] (CGPM)
 |year=2003
 |publisher=Bureau International des Poids et Measures
 |url=https://www.bipm.org/en/committees/cg/cgpm/22-2003/resolution-10 
 |access-date=2022-01-21
}}
</ref>
({{nobr|1&thinsp;000&thinsp;000&thinsp;000}} for example).<ref name=CGPM-22nd-R10/> This use has therefore been recommended by technical organizations, such as the United States' [[National Institute of Standards and Technology]].<ref>{{cite report |first1=Ambler |last1=Thompson |first2=Barry N. |last2=Taylor |date=March 2008 |title=Guide for the Use of the International System of Units (SI) |at=§10.5.3 |publisher=[[National Institute of Standards and Technology]] |url=https://physics.nist.gov/cuu/pdf/sp811.pdf#10.5.3 |access-date=21 January 2022}}</ref>

Past versions of [[ISO 8601]], but not the 2019 revision, also stipulated normative notation based on SI conventions, adding that the comma is preferred over the full stop.<ref>{{cite report |id=ISO/FDIS 8601:2000(E) |title=Data elements and interchange formats — Information interchange |section=§5.3.1.3 – Representation of dates and times |page=15 |date=2000 |publisher=[[International Standards Organisation]] |url=http://xml.coverpages.org/ISO-FDIS-8601.pdf |access-date=8 January 2019}}</ref>

[[ISO 80000-1]] stipulates that "The decimal sign is either a comma or a point on the line." The standard does not stipulate any preference, observing that usage will depend on customary usage in the language concerned, but adds a note that as per ISO/IEC directives, all ISO standards should use the comma as the decimal marker.

==Digit grouping==
<!-- Courtesy note per [[WP:RSECT]]: Several redirects link here. (Generally those with "separator" or "thousands" in their titles.) Please check with What Links here before renaming, leaving a hidden [[template:anchor]] to avoid breaking incoming links. See also [[:Talk:Decimal separator#Digit grouping and decimal separating aren't the same]]. -->

For ease of reading, numbers with many digits (e.g. numbers over 999) may be divided into groups using a [[delimiter]],<ref name="AMA10p793">{{cite book |last=Iverson |first=Cheryl |display-authors=etal |year=2007 |title=AMA Manual of Style |edition=10th |publisher=[[Oxford University Press]] |location=Oxford, UK |isbn=978-0-19-517633-9 |page=793 |url=https://archive.org/details/amamanualofstyle0000unse/page/793 }}</ref> such as comma "," or dot ".", half-space (or [[thin space]]) {{nobr|"&thinsp;",}} [[Space (punctuation)|space]] {{nobr|"&nbsp;"}}, underscore "_" (as in maritime "21_450") or apostrophe «'»<!-- f.e. in Switzerland -->. In some countries, these "digit group separators" are only employed to the left of the decimal separator; in others, they are also used to separate numbers with a long [[fractional part]]. An important reason for grouping is that it allows rapid judgement of the number of digits, via telling at a glance ("[[subitizing]]") rather than counting (contrast, for example, {{nobr|100&thinsp;000&thinsp;000}} with 100000000 for one hundred million).

The use of [[Thin space|thin spaces]] as separators,<ref name="SIBrochure">{{SIbrochure8th}}</ref>{{rp|page=133}} not dots or commas (for example: {{nobr|20&thinsp;000}} and {{nobr|1&thinsp;000&thinsp;000}} for "twenty thousand" and "one million"), has been official policy of the [[International Bureau of Weights and Measures]] since 1948 (and reaffirmed in 2003) stating
: "neither dots nor commas are ever inserted in the spaces between groups",<ref name=CGPM-22nd-R10/>

as well as of the [[International Union of Pure and Applied Chemistry]] (IUPAC),<ref name="BIPM">{{cite report |publisher=[[International Bureau of Weights and Measures]] |title=Rules and style conventions for expressing values of quantities |url=https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-10-more-printing-and-using-symbols-and-numbers}}</ref><ref name="old.iupac.org">{{cite report |title=Guidelines for drafting IUPAC technical reports and recommendations |year=2007 |url=http://old.iupac.org/reports/provisional/guidelines.html |access-date=2008-11-27}}</ref> the [[American Medical Association]]'s widely followed ''[[AMA Manual of Style]]'', and the [[Metrication Board]], among others.

The groups created by the delimiters tend to follow the use of the local language, which varies. In European languages, large numbers are read in groups of thousands, and the delimiter – which occurs every three digits when it is used – may be called a "thousands separator". In [[East Asian culture]]s, particularly [[Chinese numerals|China]], [[Japanese numerals|Japan]], and [[Korean numerals|Korea]], large numbers are read in groups of [[myriad]]s (10&nbsp;000s) but the delimiter commonly separates every three digits.{{citation needed|date=February 2014}}<!-- see talk page -->

The [[Indian numbering system]] is somewhat more complex: It groups the rightmost three digits together (until the hundreds place) and thereafter groups by sets of two digits. For example, one [[Short trillion|American trillion]] (European [[billion]]) would thus be written as 10,00,00,00,00,000 or 10 [[Indian numbering system|kharab]].<ref>{{cite report |last=Emmons |first=John |date=2018-03-25 |section=Part&nbsp;3: Numbers |title=Unicode Locale Data Markup Language (LDML) |website=Unicode.org |section-url=https://www.unicode.org/reports/tr35/tr35-numbers.html#Special_Pattern_Characters |url-status=live |access-date=2018-03-25 |archive-url=https://web.archive.org/web/20180725183458/https://www.unicode.org/reports/tr35/tr35-numbers.html#Special_Pattern_Characters |archive-date=2018-07-25}}</ref>

The convention for digit group separators historically varied among countries, but usually seeking to distinguish the delimiter from the decimal separator. Traditionally, [[English-speaking countries]] (except South Africa)<ref>{{Cite web |url=https://extranet.education.unimelb.edu.au/SME/TNMY/Decimals/Decimals/backinfo/overseas.htm |title=Language and Culture Differences. |website=extranet.education.unimelb.edu.au |accessdate=11 March 2023}}</ref> employed commas as the delimiter – 10,000 – and other European countries employed periods or spaces: 10.000 or {{nobr|10&thinsp;000}}. Because of the confusion that could result in international documents, in recent years the use of spaces as separators has been advocated by the superseded [[ISO 31-0#Numbers|SI/ISO 31-0 standard]],<ref name="nist.gov">{{cite web |title=Decimals Score a Point on International Standards |date=2006-11-22 |publisher=U.S. [[National Institute of Standards and Technology]] |url=https://www.nist.gov/public_affairs/techbeat/tb2006_1122.htm#decimal |url-status=dead |access-date=2008-11-27 |archive-url=https://web.archive.org/web/20160303171543/https://www.nist.gov/public_affairs/techbeat/tb2006_1122.htm#decimal |archive-date=2016-03-03 }}</ref> as well as by the [[International Bureau of Weights and Measures]] and the [[International Union of Pure and Applied Chemistry]], which have also begun advocating the use of a "[[thin space]]" in "groups of three".<ref name="BIPM"/><ref name="old.iupac.org"/>

Within the United States, the [[American Medical Association]]'s widely followed ''[[AMA Manual of Style]]'' also calls for a thin space.<ref name="AMA10p793"/> In programming languages and online [[character encoding|encoding]] environments (for example, [[ASCII]]-only) a thin space is not practical or available, in which case an underscore,<ref>{{cite web|url=https://peps.python.org/pep-0515/#prior-art|title=PEP 515 Underscores in Numeric Literals: Prior Art|website=peps.python.org|accessdate=2024-02-13}}</ref> regular word space, or no delimiter are the alternatives.

===Data versus mask===
Digit group separators can occur either as part of the data or as a mask through which the data is displayed. This is an example of the [[separation of presentation and content]], making it possible to display numbers with spaced digit grouping in a way that does not insert any [[whitespace character]]s into the string of digits in the [[digital content|content]]. In many computing contexts, it is preferred to omit digit group separators from the data and instead overlay them as a mask (an [[input mask]] or an output mask).

Common examples include [[spreadsheet]]s and [[database]]s in which currency values are entered without such marks but are displayed with them inserted. (Similarly, phone numbers can have hyphens, spaces or parentheses as a mask rather than as data.) In [[web content]], such digit grouping can be done with [[Cascading Style Sheets|CSS style]]. It is useful because the number can be [[cut, copy, and paste|copied and pasted]] into [[calculator]]s (including a web browser's [[omnibox]]) and parsed by the computer as-is (i.e., without the user manually purging the extraneous characters). For example, [[Wikipedia]] content can display numbers this way, as in the following examples:
:: {{val|149597870700}} metres is 1 [[astronomical unit]]
:: {{gaps|3.14159|26535|89793|23846}} is [[pi|{{pi}}]] rounded to 20 decimal places
:: {{gaps|2.71828|18284|59045|23536}} is {{mvar|[[E (mathematical constant)|e]]}} rounded to 20 decimal places.

In some [[programming language]]s, it is possible to group the digits in the program's [[source code]] to make it easier to read; see [[Integer literal#Digit separators|Integer literal: Digit separators]].
{{div col begin|colwidth=11em}}
: [[Ada programming language|Ada]]
: [[C Sharp (programming language)|C#]] {{small|(from version&nbsp;7.0)}}<ref>{{cite report |title=New Features in C#&nbsp;77.0 |section=Literal improvements |date=9 March 2017 |publisher=Microsoft |type=blog |section-url=https://devblogs.microsoft.com/dotnet/new-features-in-c-7-0/#literal-improvements |access-date=5 May 2022}}</ref> 
: [[D (programming language)|D]]
: [[Go (programming language)|Go]] {{nobr|&thinsp;{{small|(from version&nbsp;1.13)}} }}
: [[Haskell (programming language)|Haskell]] {{nobr|&emsp; {{small|(from GHC version 8.6.1)}} }}
: [[Java (programming language)|Java]]
: [[JavaScript]]
: [[Kotlin (programming language)|Kotlin]]<ref>{{cite web |title=Basic types |website=Kotlin Language |url=https://kotlinlang.org/docs/basic-types.html#literal-constants:~:text=You%20can%20use%20underscores%20to%20make%20number%20constants%20more%20readable}}</ref>
: [[OCaml]]
: [[Perl]]
: [[Python (programming language)|Python]] {{nobr|&emsp; {{small|(from version 3.6)}} }}
: [[PHP]] {{nobr|&emsp; {{small|(from version 7.4)}}<ref>{{cite web |series=PHP: New Features |title=Numeric literal separator |publisher=The PHP Group |url=https://www.php.net/manual/en/migration74.new-features.php#migration74.new-features.core.numeric-literal-separator |access-date=2020-07-16}}</ref> }}
: [[Ruby (programming language)|Ruby]]
: [[Rust (programming language)|Rust]]
: [[Zig (programming language)|Zig]]
{{div col end}}

[[Julia (programming language)|Julia]], [[Swift (programming language)|Swift]], [[Java (programming language)|Java]], and free-form [[Fortran 90]] use the [[Underscore|underscore (_)]] character for this purpose; as such, these languages allow seven hundred million to be entered as 700_000_000.

Fixed-form [[Fortran]] ignores [[whitespace character|whitespace]] (in all contexts), so 700&nbsp;000&nbsp;000 has always been accepted. [[Fortran 90]] and its successors allow (ignored) underscores in numbers in free-form.

[[C++14]], [[Rebol]], and [[Red (programming language)|Red]] all allow the use of an [[apostrophe]] for digit grouping, so 700'000'000 is permissible.

Below is shown an example of Kotlin code using separators to increase readability:
<syntaxhighlight lang="kotlin" line="1">
val exampleNumber = 12_004_953 // Twelve million four thousand nine hundred fifty-three
</syntaxhighlight>

===Exceptions to digit grouping===
The [[International Bureau of Weights and Measures]] states that "when there are only four digits before or after the decimal marker, it is customary not to use a space to isolate a single digit".<ref name=BIPM/> Likewise, some [[Style guide|manuals of style]] state that thousands separators should not be used in normal text for numbers from {{val|1000}} to {{val|9999}} inclusive where no decimal fractional part is shown (in other words, for four-digit whole numbers), whereas others use thousands separators and others use both. For example, [[APA style]] stipulates a thousands separator for "most figures of {{val|1000}} or more" except for page numbers, binary digits, temperatures, etc.

There are always "common-sense" country-specific exceptions to digit grouping, such as year numbers, [[postal code]]s, and ID numbers of predefined nongrouped format, which style guides usually point out.

===In non-base-10 numbering systems===
In binary (base-2), a full space can be used between groups of four digits, corresponding to a [[nibble]], or equivalently to a [[hexadecimal]] digit. For integer numbers, dots are used as well to separate groups of four bits.{{efn|name="DR-DEBUG_H"|
As an example, the [[DR-DOS]] [[DEBUG (DOS command)|DEBUG]] <code>H</code> command displays the entered number in hexadecimal, decimal, octal and binary notation:<pre>-h 1234
1234 #4660 \011064 %0001.0010.0011.0100</pre>
}}
Alternatively, binary digits may be grouped by threes, corresponding to an [[octal]] digit. Similarly, in hexadecimal (base-16), full spaces are usually used to group digits into twos, making each group correspond to a [[byte]].{{efn|name="DR-DEBUG_D"}} Additionally, groups of eight bytes are often separated by a hyphen.{{efn|name="DR-DEBUG_D"|
As an example, the [[DR-DOS]] [[DEBUG (DOS command)|DEBUG]] <code>D</code> command dumps the memory byte-wise in hexadecimal notation, with bytes separated by spaces and groups of eight bytes separated by hyphens:<syntaxhighlight lang="hexdump">-d 0
1234:0000  57 69 6B 69 70 65 64 69-61 20 68 65 6C 70 73 21   Wikipedia helps!</syntaxhighlight>
}}

==Influence of calculators and computers==
In countries with a decimal comma, the decimal point is also common as the "international" notation{{citation needed|date=May 2022}} because of the influence of devices, such as [[electronic calculator]]s, which use the decimal point. Most computer [[operating systems]] allow selection of the decimal separator; programs that have been carefully [[i18n|internationalized]] will follow this, but some programs ignore it and a few may even fail to operate if the setting has been changed.

Computer interfaces may be set to the Unicode international "Common locale" using {{code| LC_NUMERIC{{=}}C }} as defined at {{cite web |title=Unicode CLDR project |website=[[Unicode Consortium]] |url=http://cldr.unicode.org/index}} Details of the current (2020) definitions may be found at {{cite web |title=01102-POSIX15897 |website=[[Unicode Consortium]] |url=http://www.unicode.org/L2/L2001/01102-POSIX15897.htm}}

==Conventions worldwide==
[[File:DecimalSeparator.svg|600px|thumb|center|Decimal separators:
{{legend|#00b7ef|Dot (.)}}
{{legend|#a8e61d|Comma (,)}}
{{legend|#54ce86|Both (may vary by location or other factors)}}
{{legend|#ed1c24|[[#Other numeral systems|Arabic decimal separator]] ({{Script|Arab|٫}})}}
{{legend|#c0c0c0|Data unavailable}}]]

{{Cleanup|section and the section that follows it|reason=Use by region is inconsistent, inaccurate, and are poorly formatted.|date=March 2023}}
{{More citations needed|section|date=August 2023}}

==={{anchor|Hindu–Arabic numeral system}}Hindu–Arabic numerals===
{{clear}}
====Countries using decimal comma====
Countries where a comma "," is used as decimal separator include:

{{columns-list|colwidth=15em|
* Albania
* Algeria
* Andorra
* Angola
* Argentina
* Armenia
* Austria
* Azerbaijan
* Belarus
* Belgium
* Bolivia
* Bosnia and Herzegovina
* Brazil
* Bulgaria{{efn|group=lower-roman|name=fn3|The comma as a decimal separator is the national literary convention, but many places use the dot as decimal separator due to prevalence of imported tech that internally uses dot as the decimal separator (because the tech usually utilizes the dot decimal separator convention of the country where it was made, which is mostly USA-&-[[ASCII]]-oriented, or is made in China where the dot is utilized as a decimal separator). To sum up, the comma is the conventional decimal separator in Bulgaria, but both the comma and the dot are in ''de facto'' usage.}}
* Cabo Verde
* Cameroon
* Canada (when using French)
* Chile
* Colombia
* Costa Rica
* Croatia
* Cuba
* Cyprus
* Czech Republic
* Denmark
* East Timor
* Ecuador
* Estonia
* Faroes
* Finland
* France
* Germany
* Georgia
* Greece
* Greenland
* Hungary
* Iceland
* Indonesia
* Italy
* Kazakhstan
* Kyrgyzstan
* Laos
* Latvia
* Lebanon
* Lithuania
* Luxembourg
* Macau (in Portuguese text)
* Mauritania
* Moldova
* Mongolia{{efn|group=lower-roman|name=fn4|The comma as a decimal separator is the national literary convention, but many places use the dot as decimal separator due to prevalence of imported tech that internally uses dot as the decimal separator (because the tech usually utilizes the dot decimal separator convention of the country where it was made, which is mostly USA-&-[[ASCII]]-oriented, or is made in China where the dot is utilized as a decimal separator). To sum up, the comma is the conventional decimal separator in Mongolia, but the dot is more commonly used.}}
* Montenegro
* Morocco
* Mozambique
* Namibia (uses both marks)<ref>{{cite web|title=AirNam board endorses aircraft purchase plan|url=http://www.mpe.gov.na/documents/182025/256446/AirNam+board+endorses+aircraft+purchase+plan.pdf/|website=Republic of Namibia, Ministry of Public Enterprises|access-date=30 January 2018|quote=The cost per aircraft was estimated at between N$19,5 million and N$26 million.|archive-date=31 January 2018|archive-url=https://web.archive.org/web/20180131024141/http://www.mpe.gov.na/documents/182025/256446/AirNam+board+endorses+aircraft+purchase+plan.pdf/|url-status=dead}}</ref>
* The Netherlands
* North Macedonia
* Norway
* Paraguay
* Peru<ref>{{cite web|title=DECRETO SUPREMO Nº 064-84-ITI/IND|url=https://www.inacal.gob.pe/repositorioaps/data/1/1/5/jer/mlegal/files/DS-064-84-ITI-IND.pdf|website=Instituto Nacional de Calidad (INACAL)|access-date=23 March 2019|quote=La escritura de los números se hará utilizando las cifras arábigas y la numeración decimal, y en ella se separará la parte entera de la decimal mediante una coma (,).}}</ref>
* Poland
* Portugal
* Romania
* Russia
* San Marino 
* Serbia
* Slovakia
* Slovenia
* Somalia 
* South Africa<ref name=za>{{cite book |last=GCIS (2011) |url=http://www.gcis.gov.za/sites/default/files/editorial_styleguide_2011.pdf |title=Editorial Style Guide |publisher=Government Communications & Information System |location=Pretoria |page=24 |access-date=2018-01-30|quote=* Write decimal and negative numbers as numerals: 3,3 and –4. Use the decimal comma, not the decimal point: 17,4 million. [...] * Use a space, not commas, to indicate thousands: 3 000, 20 000.}}</ref><ref name=za-sadev>{{cite web|last1=MacLean|first1=Robert|title=How to correctly format currency in South Africa?|url=https://sadev.co.za/content/how-correctly-format-currency-south-africa|access-date=4 February 2018}}<br/></ref>
* Spain{{efn|group=lower-roman|name=fn2}}
* Suriname
* Sweden{{efn|group=lower-roman|name=fn2}}
* Switzerland{{efn|group=lower-roman|name=fn1}}
* Tunisia
* Turkey
* Turkmenistan
* Ukraine
* Uruguay
* Uzbekistan
* Venezuela
* Vietnam
* Zimbabwe
}}

{{anchor|Dot countries}}

====Countries using decimal point====
Countries where a dot "." is used as decimal separator include:

{{columns-list|colwidth=15em|
* Australia
* Bahamas, The
* Bangladesh
* Botswana
* British West Indies
* Cambodia
* Canada (when using English)
* China
* Cyprus (currency numbers)
* Dominican Republic
* Egypt
* El Salvador
* Ethiopia
* Ghana
* Guatemala
* Guyana
* Honduras
* Hong Kong
* India
* Ireland
* Israel
* Jamaica
* Japan
* Jordan
* Kenya
* Korea, North
* Korea, South
* Libya
* Liechtenstein
* Macau (in Chinese and English text)
* Malaysia
* Maldives
* Malta
* Mexico
* Myanmar
* Namibia (uses both marks)
* Nepal
* New Zealand
* Nicaragua
* Nigeria
* Pakistan
* Panama
* Peru (currency numbers)
* Philippines
* Qatar
* Saudi Arabia
* Singapore
* Somalia
* Sri Lanka
* Switzerland{{efn|group=lower-roman|name=fn1|The decimal point is used in some [[Cantons of Switzerland|cantons]] (for example the [[Canton of St. Gallen]]<ref>[http://www.schule.sg.ch/home/volksschule/unterricht/lehrplan/_jcr_content/Par/downloadlist_0/DownloadListPar/download_6.ocFile/8_Fachbereich_Mathematik.pdf Lehrplan Fachbereich Mathematik] {{Webarchive|url=https://web.archive.org/web/20170323143437/http://www.schule.sg.ch/home/volksschule/unterricht/lehrplan/_jcr_content/Par/downloadlist_0/DownloadListPar/download_6.ocFile/8_Fachbereich_Mathematik.pdf |date=2017-03-23 }}, p. 14 (PDF; ≈&nbsp;257&nbsp;kB) – from ''schule.sg.ch'' (german)</ref>) and is used in [[Information technology|IT]] and for [[currency]]. The decimal comma is used for federal publications<ref>''[http://www.bk.admin.ch/dokumentation/sprachen/04915/05016/index.html?lang=de Schreibweisungen; 514: Dezimalkomma und Dezimalpunkt] {{Webarchive|url=https://web.archive.org/web/20170122114658/http://www.bk.admin.ch/dokumentation/sprachen/04915/05016/index.html?lang=de |date=2017-01-22 }}'' – Issuer: ''[[Federal Chancellery of Switzerland]]'', 2nd issue 2013, p. 80 (German).</ref> and some [[Cantons of Switzerland|cantons]].}}
* Syria
* Taiwan
* Tanzania
* Thailand{{efn|group=lower-roman|name=fn2|According to several software developers.<ref name=software>{{cite web|publisher=Oracle|title=Decimal and Thousands Separators|url=https://docs.oracle.com/cd/E19455-01/806-0169/overview-9/index.html|access-date=2019-03-18}}</ref><ref>{{cite web|first1=Igor|last1=Krupitsky|publisher=Microsoft|title=International Number Formats|date=May 2010|url=https://www.codeproject.com/Articles/78175/International-Number-Formats|access-date=2019-03-18}}</ref>}}
* Uganda
* United Arab Emirates
* United Kingdom
* United States (including [[insular area]]s)
}}Notes:{{notelist|group=lower-roman}}

===Other numeral systems===
Unicode defines a ''decimal separator key symbol'' (⎖ in hex U+2396, decimal 9110) which looks similar to the [[apostrophe]]. This symbol is from [[ISO/IEC 9995]] and is intended for use on a keyboard to indicate a key that performs decimal separation.

In the [[Arab world]], where [[Eastern Arabic numerals]] are used for writing numbers, a different character is used to separate the integer and fractional parts of numbers. It is referred to as an [[Arabic (Unicode block)|Arabic decimal separator]] (U+066B, rendered: {{Script|Arab|٫}}) in [[Unicode]]. An Arabic thousands separator (U+066C, rendered: {{Script|Arab|٬}}) also exists. Example: {{Script|Arab|۹٬۹۹۹٫۹۹}} (9,999.99)

In [[Persian language|Persian]], the decimal separator is called [[momayyez]]. The Unicode Consortium's investigation concluded that "computer programs should render U+066B as a shortened, lowered, and possibly more slanted [[Slash (punctuation)|slash]] ({{Script|fa-Arab|٫}}); this should be distinguishable from the slash at the first sight." To separate [[sequence]]s of three digits, an Arabic thousands separator (rendered as: {{Script|fa-Arab|٬}}), a Latin comma, or a [[space (punctuation)|blank space]] may be used; however this is not a standard.<ref>{{cite web |url=http://unicode.org/mail-arch/unicode-ml/Archives-Old/UML024/1289.html |title=Persian decimal separator |last=Pournader |first=Roozbeh |date=2000-10-15 |work=Unicode Mail List Archive |publisher=Unicode Consortium |access-date=2008-06-21}}</ref><ref>{{cite web
 |url=http://www.fazel.de/dastur/EN/2-1-05-001-1-3_decimal_numeral.html 
 |title=The Decimal Numeral 
 |work=Academic Grammar of New Persian 
 |access-date=2006-06-19 
 |archive-url=https://web.archive.org/web/20060620042521/http://www.fazel.de/dastur/EN/2-1-05-001-1-3_decimal_numeral.html 
 |archive-date=2006-06-20 
 |url-status=dead 
}}</ref><ref>{{cite web|url=http://www.fazel.de/dastur/EN/2-1-05-001-1-3_decimal_numeral.html |title=Descriptive Grammar of New Persian (archived) |access-date=2019-05-01|archive-url=https://web.archive.org/web/20070711041230/http://www.fazel.de/dastur/EN/2-1-05-001-1-3_decimal_numeral.html |archive-date=2007-07-11 }}</ref> Example: {{Script|fa-Arab|۹٬۹۹۹٫۹۹}} (9,999.99)

In [[English Braille]], the decimal point, {{bc|46}}, is distinct from both the comma, {{bc|2}}, and the full stop, {{bc|256}}.

==Examples of use==
The following examples show the decimal separator and the thousands separator in various countries that use the Arabic numeral system.

{| class="wikitable"
|-
! Style !! Countries and regions
|-
| style="text-align:right;"| 1'''<nowiki>,</nowiki>'''234'''<nowiki>,</nowiki>'''567'''<nowiki>.</nowiki>'''89 || Australia,<ref>{{cite web|url=https://www.stylemanual.gov.au/style-rules-and-conventions/numbers-and-measurements/choosing-numerals-or-words#combine_numerals_and_words_for_large_rounded_numbers|title=Digital Guides|publisher=Australian Government|access-date=19 August 2020}}</ref><ref>{{cite web|url=https://about.abc.net.au/abc-editorial/the-abc-style-guide/#T|title=The ABC Style Guide|publisher=Australian Broadcasting Corporation|access-date=19 August 2020}}</ref> Cambodia, Canada (English-speaking; unofficial), China,<ref>{{cite web|url=https://openstd.samr.gov.cn/bzgk/gb/newGbInfo?hcno=F5DAC3377DA99C8D78AE66735B6359C7|title=国家标准GB/T 15835-2011出版物上数字用法|publisher=国家标准全文公开系统|access-date=2 April 2024}}</ref> Cyprus (currency numbers), Hong Kong, Iran, Ireland, Israel, Japan, Korea, Macau (in Chinese and English text), Malaysia, Mexico, Namibia, New Zealand, Pakistan, Peru (currency numbers), Philippines, Singapore, South Africa (English-speaking; unofficial), Taiwan, Thailand, United Kingdom and other Commonwealth states except Mozambique, United States.
|-
| style="text-align:right;"| {{gaps|1|234|567'''<nowiki>.</nowiki>'''89}} || Canada (English-speaking; official), China,<ref>{{cite web|url=https://openstd.samr.gov.cn/bzgk/gb/newGbInfo?hcno=F5DAC3377DA99C8D78AE66735B6359C7|title=国家标准GB/T 15835-2011出版物上数字用法|publisher=国家标准全文公开系统|access-date=2 April 2024}}</ref> Estonia (currency numbers), Hong Kong (in education), Mexico, Namibia, South Africa (English-speaking; unofficial), Sri Lanka, Switzerland (in federal texts for currency numbers only<ref name="bk_admin_ch">{{cite web |publisher=Schweizer Bundeskanzlei |url=https://www.admin.ch/gov/de/start/dokumentation/medienmitteilungen.msg-id-49648.html |title=Schreibweisungen, 2nd edition 2013 |date=June 2013 |archive-url=https://web.archive.org/web/20150128123857/http://www.bk.admin.ch/dokumentation/sprachen/04915/05016/index.html?lang=de&download=NHzLpZeg7t,lnp6I0NTU042l2Z6ln1acy4Zn4Z2qZpnO2Yuq2Z6gpJCHe393gWym162epYbg2c_JjKbNoKSn6A-- |archive-date= 28 January 2015}}</ref>), United Kingdom (in education), United States (in education){{Citation needed|date=September 2024|reason=Based on my experience, the overwhelming majority of academia in the US uses the thousand separator.}}.  SI style (English version) but SI doesn't include currency.
|-
| style="text-align:right;"| {{gaps|1|234|567'''<nowiki>,</nowiki>'''89}} || Albania, Belgium (French), Brazil, Bulgaria, Canada (French-speaking), Costa Rica, Croatia, Czech Republic, Estonia, Finland,<ref>{{cite web|url=http://www.kielitoimistonohjepankki.fi/ohje/49|title=Luvut ja numerot: numeroiden ryhmittely|website=Kielitoimiston ohjepankki|language=fi-FI|access-date=2018-06-27}}</ref> France, Hungary, Italy (in education), Latin America, Latin Europe, Latvia, Lithuania, Macau (in Portuguese text), Mozambique, Norway, Peru, Poland, Portugal, Russia, Serbia (informal), Slovakia, Slovenia, South Africa (official<ref name=SAHPRA>{{cite report |url=https://www.sahpra.org.za/wp-content/uploads/2020/01/2.38_SI_Metric_System_Mar19_v3.pdf |title=SI Metric System |date=March 2019 |edition=2.38 |website=SAHPRA |quote=The comma is the only recognised decimal indicator for all numbers, including amounts of (currency) money.}}</ref>), Spain (official use since 2010, according to the ''[[Royal Spanish Academy|RAE]]'' and ''[[Spanish National Research Council|CSIC]]''), Sweden, Switzerland (in federal texts, except currency numbers<ref name=bk_admin_ch/>), Ukraine, Vietnam (in education).  SI style (French version) but SI doesn't include currency.
|-
| style="text-align:right;"| 1'''<nowiki>.</nowiki>'''234'''<nowiki>.</nowiki>'''567'''<nowiki>,</nowiki>'''89 || Austria, Belgium (Dutch), Bosnia and Herzegovina, Brazil (informal and in [[technology]]), Chile, Colombia, Croatia (in [[bookkeeping]] and technology),<ref name=":1">{{Cite web |title=Točka |website=Hrvatski pravopis |publisher=[[Institute of Croatian Language and Linguistics]] |url=http://pravopis.hr/pravilo/tocka/55/ |access-date=2022-07-28}}</ref> Denmark, Germany, Greece, Indonesia, Italy, Latin America (informal), Netherlands, Romania, Slovenia, Serbia, Spain (used until 2010, inadvisable use according to the ''[[Royal Spanish Academy|RAE]]'' and [[Spanish National Research Council|''CSIC'']]),{{efn|... when writing numbers more than four figures, these will be grouped into threes, starting from the right, and separating the groups by whitespace. (Exceptions: Never written with periods, commas or white separation numbers that refer to years, pages, verses, urban roads, postal codes, legal articles, decrees or laws.)<ref name=test>{{cite book |title=Diccionario panhispánico de dudas |url=http://lema.rae.es/dpd/srv/search?key=n%FAmeros#2 |url-status=dead |access-date=16 January 2014 |archive-date=18 January 2014 |archive-url=https://web.archive.org/web/20140118023207/http://lema.rae.es/dpd/srv/search?key=n%FAmeros#2 }}</ref>}}<ref name=Ortografia>{{cite book |title=Ortografía de la lengua española |quote=For the purpose of promoting a process tending towards unification, the use of the point as decimal separator is recommended.(2.2.1.2.1) |url=http://aplica.rae.es/orweb/cgi-bin/v.cgi?i=KnJfwDWVQQYgmiw,}}</ref> Turkey, Uruguay, Vietnam.
|-
| style="text-align:right;"| 1'''<nowiki>,</nowiki>'''234'''<nowiki>,</nowiki>'''567'''<nowiki>·</nowiki>'''89 || Malaysia, Malta, Philippines (uncommon today), Singapore, Taiwan, United Kingdom (older, typically handwritten; in education)
|-
| style="text-align:right;"| 12'''<nowiki>,</nowiki>'''34'''<nowiki>,</nowiki>'''567'''<nowiki>.</nowiki>'''89 || rowspan="2" | Bangladesh, India, Nepal, Pakistan (see [[Indian numbering system]]).
|-
|{{Gaps|12|34|567'''<nowiki>.</nowiki>'''89}}
|-
| style="text-align:right;"| 1'''<nowiki>'</nowiki>'''234'''<nowiki>'</nowiki>'''567'''<nowiki>.</nowiki>'''89 || Switzerland (computing), Liechtenstein.
|-
| style="text-align:right;"| 1'''<nowiki>'</nowiki>'''234'''<nowiki>'</nowiki>'''567'''<nowiki>,</nowiki>'''89 || Switzerland (handwriting), Italy (handwriting).
|-
| style="text-align:right;"| 1'''<nowiki>.</nowiki>'''234'''<nowiki>.</nowiki>'''567'''<nowiki>'</nowiki>'''89 || Spain (handwriting, used until 1980s, inadvisable use according to the [[Royal Spanish Academy|''RAE'']] and ''[[Spanish National Research Council|CSIC]]''{{Citation needed|date=October 2009}}).
|}

*In Belgium (Dutch), Brazil, Denmark, Germany, Greece, Indonesia, Italy, Netherlands, Portugal, Romania, Russia, Slovenia, Sweden and much of Europe: {{gaps|1|234|567'''<nowiki>,</nowiki>'''89}} or 1'''<nowiki>.</nowiki>'''234'''<nowiki>.</nowiki>'''567'''<nowiki>,</nowiki>'''89. In [[handwriting]], 1'''<nowiki>˙</nowiki>'''234'''<nowiki>˙</nowiki>'''567'''<nowiki>,</nowiki>'''89 is also seen, but never in Belgium, Brazil, Denmark, Estonia, Germany, the Netherlands, Portugal, Romania, Russia, Slovenia or Sweden. In Italy, a straight apostrophe is also used in handwriting: 1'''<nowiki>'</nowiki>'''234'''<nowiki>'</nowiki>'''567'''<nowiki>,</nowiki>'''89. In the Netherlands and Dutch-speaking Belgium, the points thousands separator is used, and is preferred for currency amounts, but the space is recommended by some style guides, mostly in technical writing.<ref>{{cite web|url=http://taaladvies.net/taal/advies/vraag/1/10000000_10_000_000/|title=10.000.000&nbsp;/&nbsp;10&nbsp;000&nbsp;000|author=Taalunieversum|access-date=1 September 2017}}</ref>
*In Estonia, currency numbers often use a dot "'''<nowiki>.</nowiki>'''" as the decimal separator, and a space as a thousands separator. This is most visible on shopping receipts and in documents that also use other numbers with decimals, such as measurements. This practice is used to better distinguish between prices and other values with decimals. An older convention uses dots to separate thousands (with commas for decimals) &mdash; this older practice makes it easier to avoid word breaks with larger numbers.
*Historically, in Germany and Austria, thousands separators were occasionally denoted by alternating uses of comma and point, e.g. 1'''<nowiki>.</nowiki>'''234'''<nowiki>,</nowiki>'''567'''<nowiki>.</nowiki>'''890'''<nowiki>,</nowiki>'''12<ref>{{cite web |last=Röll |title=Union Pacific-Eisenbahn |work=Enzyklopädie des Eisenbahnwesens |url=http://www.zeno.org/Roell-1912/A/Union+Pacific-Eisenbahn |access-date=26 August 2014}}, entry "Union Pacific-Eisenbahn", largest numbers in table</ref><ref>{{cite web |last=Röll |title=Bilanz |work=Enzyklopädie des Eisenbahnwesens |url=http://www.zeno.org/Roell-1912/A/Bilanz |access-date=26 August 2014}}, entry "Bilanz", sums in last table</ref> for "eine Milliarde 234 Millionen ...", but this is never seen in modern days and requires explanation to a contemporary German reader.
*Switzerland: There are two cases: An apostrophe as a thousands separator along with a dot "'''<nowiki>.</nowiki>'''" as the decimal separator are used for currency values (for example: 1'''<nowiki>'</nowiki>'''234'''<nowiki>'</nowiki>'''567'''<nowiki>.</nowiki>'''89). For other values, the [[SI]]-style {{gaps|1|234|567'''<nowiki>,</nowiki>'''89}} is used with a comma "'''<nowiki>,</nowiki>'''" as the decimal separator. The apostrophe is also the most common variety for non-currency values: 1'''<nowiki>'</nowiki>'''234'''<nowiki>'</nowiki>'''567'''<nowiki>,</nowiki>'''89 &mdash;.
*In Ireland, Israel, Japan, [[Korea]] (both), Malaysia, the Philippines, Singapore, Taiwan, Thailand, the United Kingdom, and the United States: 1,234,567'''<nowiki>.</nowiki>'''89 or 1,234,567'''<nowiki>·</nowiki>'''89; the latter is generally found only in older, and especially [[Manuscript|handwritten]] documents. 
*English Canada: There are two cases: The preferred method for currency values is $10'''<nowiki>,</nowiki>'''000'''<nowiki>.</nowiki>'''00 &mdash;while for numeric values, it is {{gaps|1|234|567'''<nowiki>.</nowiki>'''89}}; however, commas are also sometimes used, although no longer taught in school or used in official publications.{{Citation needed|date=September 2016}}
*[[International System of Units|SI]] style: {{gaps|1|234|567'''<nowiki>.</nowiki>'''89}} or {{gaps|1|234|567'''<nowiki>,</nowiki>'''89}} (in their own publications, the dot "'''<nowiki>.</nowiki>'''" is used in the English version, and the comma "'''<nowiki>,</nowiki>'''" in the official French version).
*In China, comma and space are used to mark digit groups, because dot is used as decimal separator. There is no universal convention on digit grouping, so both thousands grouping and no digit grouping can be found. Japan and Taiwan are similar; although when grouping by myriads, [[Japanese numerals|kanji]] or [[Chinese numerals|characters]] are frequently used as separators: 1億2345万6789 / 1億2345萬6789. Commas are used when grouping by thousands.
*In [[India]], due to a numeral system using ''[[lakh]]s'' (''lacs'') (1'''<nowiki>,</nowiki>'''23'''<nowiki>,</nowiki>'''456 equal to 123'''<nowiki>,</nowiki>'''456) and ''[[crore]]s'' (1'''<nowiki>,</nowiki>'''23'''<nowiki>,</nowiki>'''45'''<nowiki>,</nowiki>'''678 equal to {{nowrap|12'''<nowiki>,</nowiki>'''345'''<nowiki>,</nowiki>'''678}}), a comma is used at levels of thousand, lakh, and crore. For example, 10 million (1 crore) would be written as 1'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''000. In [[Pakistan]], there is a greater tendency to use the standard western system, while using the Indian numbering system when conducting business in [[Urdu]].
*In [[Sweden]], the currency sometimes used the colon as decimal separator (1 234 567:89).

{|class="wikitable" style="text-align:center;"
|-
!Indian value
!Value
!Equivalent western notation
|-
|scope="row" |One
| style="text-align:right;"|1
|One
|-
|scope="row" |Ten
| style="text-align:right;"|10
|Ten
|-
|scope="row" |Hundred
| style="text-align:right;"|100
|Hundred
|-
|scope="row" |Thousand
| style="text-align:right;"|1'''<nowiki>,</nowiki>'''000
|Thousand
|-
|scope="row" |Lakh
| style="text-align:right;"|1'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''000
|One hundred thousand
|-
|scope="row" |Crore
| style="text-align:right;"|1'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''000
|Ten million
|-
|scope="row" | Arab (not normally used)
| style="text-align:right;"|1'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''000
|One [[Long and short scales|short]] billion (one thousand million)
|-
|scope="row" | Kharab (not normally used)
| style="text-align:right;"|1'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''000
|One hundred short billion
|-
|scope="row" | Lakh crore 
| style="text-align:right;"|10'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''00'''<nowiki>,</nowiki>'''000
|One short trillion (one long (European) billion)
|}
{{Clear|Left}}

==Unicode characters==

Used with [[Western Arabic numerals]] (0123456789):
* {{unichar|0020|SPACE|html=}}
* {{unichar|0027|APOSTROPHE|html=}}
* {{unichar|002C|COMMA|html=}}
* {{unichar|002E|FULL STOP|html=}} - [[Full stop|Full stop punctuation mark.]]
* {{unichar|00B7|MIDDLE DOT|html=}}
* {{unichar|2009|thin space|html=}}
* {{unichar|202F|[[narrow no-break space]]|html=}}
* {{unichar|02D9|DOT ABOVE|html=}}

Used with [[Eastern Arabic numerals]] (٠١٢٣٤٥٦٧٨٩):
* {{unichar|066B|ARABIC DECIMAL SEPARATOR|html=}}
* {{unichar|066C|ARABIC THOUSANDS SEPARATOR|html=}}

Used with keyboards:
* {{unichar|2396|DECIMAL SEPARATOR KEY SYMBOL|html=}} (resembles an apostrophe)

==See also==
{{div col begin|colwidth=15em}}
* [[Algorism]]
* [[Cifrão]]
* [[Decimal floating point]]
* [[Decimal place]]
* [[Decimal representation]]
* ''[[Scriptio continua]]''
* [[Space (punctuation)]]
* [[Decimal section numbering]]
* [[Dot-decimal notation]]
* [[International System of Units]]
* [[ISO 2145]]
* [[RKM code]]
* [[Version numbering]]
{{div col end}}

==Footnotes==
{{notelist}}

==References==
{{reflist|25em}}

{{DEFAULTSORT:Decimal mark}}
[[Category:Positional numeral systems]]
[[Category:Punctuation]]
[[Category:Internationalization and localization]]