View source for Decimal separator

{{Short description|Numerical symbol}}
{{Redirect|Decimal period|the period of a repeating decimal fraction|Repeating decimal}}
{{Use dmy dates|date=November 2022}}
{{Numeral systems}}

[[FIle:Decimal separators.svg|thumb|alt=Four types of separating decimals: a) 1,234.56. b) 1.234,56. c) 1'234,56. d) ١٬٢٣٤٫٥٦.|Both a [[comma]] and a [[full stop]] (or period) are generally accepted decimal separators for international use. The [[apostrophe]] and Arabic decimal separator are also used in certain contexts.]]
[[File:Thousands separators.gif|thumb|Three ways to group the number ten thousand with digit group separators: {{blist
  | [[Space (punctuation)|Space]], the internationally recommended thousands separator.
  | [[Full stop]] (or period), the thousands separator used in many non-English speaking countries.
  | [[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. Different countries officially designate different symbols for use as the separator. The choice of symbol can also affect the choice of symbol for the [[#Digit grouping|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|pmid=38374392 |url-access=subscription }}</ref>{{contradictory inline|History of mathematical notation#Indian and Arabic numerals and notation|date=April 2025}}

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.<ref>{{cite magazine|title=Signposts: Directions for the Traveler Are Hundreds of Years Old|first=George M.|last=Webb|work=[[California Highways and Public Works]]|location=Sacramento, California|publisher=California Division of Highways|volume=35|issue=5–6|date=May–June 1956|page=11|url=https://libraryarchives.metro.net/dpgtl/californiahighways/chpw_1956_mayjun.pdf#page=13}}</ref> 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, whilst 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 |language=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 whilst 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 but, somewhat unusually, the middle dot as its 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++14#Digit separators|C++]] and a few others permit a quote (') as a thousands separator, while others like Python and Julia only allow '_' as such a separator (this separator is ignored by the computer, so it can be used flexibly. For example, a programmer could write <code>1_00_00_000</code> to match the Indian numbering system's format for ten million, <code>1,00,00,000</code>.)

=== 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 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, Florida |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'' (with [[wiktionary:deci-|deci-]] indicating [[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 31-0 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]] (base&nbsp;2) representation, it may be called "binary point".

==Current international standards==
The 22nd [[General Conference on Weights and Measures]]<ref name=CGPM-22nd-R10/> declared in 2003, "The symbol for the decimal marker shall be either the point on the line or the comma on the line." It further reaffirmed,<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>
{{blockquote|text=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}}
That is, "{{nobr|1&thinsp;000&thinsp;000&thinsp;000}}" is preferred over "1,000,000,000" or "1.000.000.000". This use has therefore been recommended by technical organizations, such as the United States's [[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, "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 ({{code|,}}), dot ({{code|.}}), half-space or [[thin space]] ({{nobr|"&thinsp;"}}), [[Space (punctuation)|space]] ({{nobr|"&nbsp;"}}), underscore ({{code|_}}; as in maritime "21_450"),{{citation needed|date=April 2025}} or apostrophe ({{code|'}})<!-- 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 spaces as separators<ref name="SIBrochure">{{SIbrochure8th}}</ref>{{rp|page=133}} instead of 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]] (BIPM) since 1948 (and reaffirmed in 2003),<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 UK [[Metrication Board]], among others.

The groups created by the delimiters tend to follow the usages of local languages, which vary. In European languages, large numbers are read in groups of thousands, and the delimiter (occurring every three digits when 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 ({{nobr|10 000s}}), but the delimiter often separates the digits into groups of three.{{citation needed|date=February 2014}}<!-- see talk page -->

The [[Indian numbering system]] is more complex: It groups the rightmost three digits together (until the hundreds place) and then groups digits in sets of two. For example, one trillion would be written "10,00,00,00,00,000" or "{{nobr|10 [[Indian numbering system|{{translit|hi|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 sought 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 (full stops) 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 BIPM and IUPAC. These groups 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 languages and environments) a thin space is not practical or available. Often, either underscores<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> and regular word spaces, or no delimiters at all are used instead.

===Data vis-à-vis 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 in spaced groups while not inserting any [[whitespace character]]s into the string of digits that make up those numbers. In many computing contexts, it is preferred to omit the 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]], digit grouping can be done with [[CSS]]. This is useful because the number can be copied and pasted elsewhere (such as into a calculator) and parsed by the computer as-is (i.e., without the user manually purging the extraneous characters). For example:
{{block indent |left=1.5 |text={{plainlist}}
* {{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.
{{endplainlist}}}}

In many [[programming language]]s, it is possible to group the digits in the program's [[source code]] to make it easier to read {{crossreference|(see: {{section link|Integer literal#Digit separators}})}}.

[[Ada (programming language)|Ada]], Free-form [[Fortran 90]], [[Perl]], [[D (programming language)|D]], [[OCaml]], [[Ruby (programming language)|Ruby]], [[Java (programming language)|Java]], [[Rust (programming language)|Rust]], [[Julia (programming language)|Julia]], [[Python (programming language)|Python]] (since {{nobr|version 3.6}}), [[Kotlin (programming language)|Kotlin]],<ref>{{cite web |title=Numbers {{!}} Kotlin Documentation |url=https://kotlinlang.org/docs/numbers.html#literal-constants-for-numbers |access-date=2025-08-20 |website=Kotlin Language}}</ref> [[C Sharp (programming language)|C#]] (since {{nobr|version 7.0}}),<ref>{{cite report |title=New Features in C#&nbsp;77.0 |date=9 March 2017 |publisher=Microsoft |access-date=5 May 2022 |section=Literal improvements |type=blog |section-url=https://devblogs.microsoft.com/dotnet/new-features-in-c-7-0/#literal-improvements}}</ref> [[Swift (programming language)|Swift]], [[Haskell (programming language)|Haskell]] (from GHC {{nobr|version 8.6.1}}), [[Go (programming language)|Go]] (since {{nobr|version 1.13}}), [[PHP]] (since {{nobr|version 7.4}}),<ref>{{cite web |title=Numeric literal separator |url=https://www.php.net/manual/en/migration74.new-features.php#migration74.new-features.core.numeric-literal-separator |access-date=2020-07-16 |series=PHP: New Features |publisher=The PHP Group}}</ref> [[Zig (programming language)|Zig]],<ref>{{Cite web |title=Documentation - The Zig Programming Language |url=https://ziglang.org/documentation/master/#Integer-Literals |access-date=2025-08-20}}</ref> and [[JavaScript]] (since ES2021) have adopted the [[underscore]] ({{code|_}}) character for this purpose. As such, these languages would allow the number seven hundred million to be entered as "700_000_000". On the other hand, fixed-form Fortran ignores whitespace in all contexts, so "{{nobr|700 000 000}}" would be allowed. In [[C++14]], [[Rebol]] and [[Red (programming language)|Red]], the use of an [[apostrophe]] for digit grouping is allowed. Thus, "700'000'000" would be allowed in those languages.

The code shown below, written in Kotlin, illustrates the use of separators to increase readability:
<syntaxhighlight lang="kotlin" line="1">
val exampleNumber = 12_000_000 // twelve million
</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}} where no decimal fractional part is shown (or, 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}} command (short for 'hex') displays the entered hexadecimal number in hexadecimal, followed by the same number in decimal, octal, and binary, prefixed with a hash sign ({{code|#}}), backslash ({{code|\}}), and percent sign ({{code|%}}) respectively:
<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}} command (short for 'dump') 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==
{{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}}

[[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}}]]

===Hindu–Arabic numerals<span class="anchor" id="Hindu–Arabic numeral system"></span> ===
{{clear}}

====Countries using decimal comma====
Countries where a comma ({{code|,}}) is used as a 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=bulgaria-mongolia|The national literary convention in Bulgaria and Mongolia is to use the comma as a decimal separator, but many places use the dot instead due to the prevalence of imported technology that internally uses the dot as the decimal separator. This is because the technology usually utilizes the decimal separator conventions of the country it was made in, and most of the technology is made in the United States, countries following the conventions and standards (such as [[ASCII]]) of the United States, or China – all of which use the dot as a decimal separator. Thus, in Bulgaria, the comma is the conventional decimal separator, but both the comma and the dot are used in practice. This is true for Mongolia as well, but the dot is more commonly used instead.}}
* 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=bulgaria-mongolia}}
* 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=software-devs}}
* Suriname
* Sweden{{efn|group=lower-roman|name=software-devs}}
* Switzerland{{efn|group=lower-roman|name=switzerland}}
* Tunisia
* Turkey
* Turkmenistan
* Ukraine
* Uruguay
* Uzbekistan
* Venezuela
* Vietnam
* Zimbabwe
}}

{{anchor|Dot countries}}
====Countries using decimal point====
Countries where a dot ({{code|.}}) is used as a 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=switzerland|The decimal point is used in some [[cantons of Switzerland]] (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>). It is used in [[IT]] and with [[currency]] values. On the other hand, the decimal comma is used in 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 other cantons.}}
* Syria
* Taiwan
* Tanzania
* Thailand{{efn|group=lower-roman|name=software-devs|According to several software developers, Spain and Sweden both use a comma as a decimal separator while Thailand uses a dot instead.<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 {{translit|fa|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, {{braille cell|46}}, is distinct from both the comma, {{braille cell|2}}, and the full stop, {{braille cell|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;" | 1,234,567.89 || 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 name="SAMR2011">{{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|date=2011-07-29|language=zh|trans-title=General rules for writing numerals in public texts}}</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|567.89}} || Canada (English-speaking; official), China,<ref name="SAMR2011" /> 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.news.admin.ch/de/nsb?id=49648 |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), not including currency.
|-
| style="text-align: right;" | {{gaps|1|234|567,89}} || Albania, Belgium, 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, Germany, 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), not including currency.
|-
| style="text-align: right;" | 1.234.567,89 || Austria, 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 ''RAE'' and ''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=https://www.rae.es/ortograf%C3%ADa/los-n%C3%BAmeros-decimales-y-el-separador-decimal#2.2.1.2.1}}</ref> Turkey, Uruguay, Vietnam.
|-
| style="text-align: right;" | 1,234,567·89 || Malaysia, Malta, Philippines (uncommon today), Singapore, Taiwan, United Kingdom (older, typically handwritten; in education)
|-
| style="text-align: right;" | 12,34,567.89 || rowspan="2" | Bangladesh, India, Nepal, Pakistan {{crossreference|(see: [[Indian numbering system]])}}.
|-
| {{Gaps|12|34|567.89}}
|-
| style="text-align: right;" | 1'234'567.89 || Switzerland (computing), Liechtenstein.
|-
| style="text-align: right;" | 1'234'567,89 || Switzerland (handwriting), Italy (handwriting).
|-
| style="text-align: right;" | 1.234.567'89 || Spain (handwriting, used until 1980s, inadvisable use according to the ''RAE'' and ''CSIC'').<ref name=Ortografia2>{{cite book |title=Ortografía de la lengua española |quote=The use of the apostrophe instead of the comma to separate the decimal part is not correct and should be avoided.(2.2.1.2.1) |url=https://www.rae.es/ortograf%C3%ADa/los-n%C3%BAmeros-decimales-y-el-separador-decimal#2.2.1.2.1}}</ref>
|}

* In Belgium (Dutch), Brazil, Denmark, Germany, Greece, Indonesia, Italy, Netherlands, Portugal, Romania, Russia, Slovenia, Sweden and much of Europe, "{{gaps|1|234|567,89}}" or "1.234.567,89" are seen. In [[handwriting]], "1˙234˙567,89" is also seen, but never in Belgium, Brazil, Denmark, Estonia, Germany, the Netherlands, Portugal, Romania, Russia, Slovenia or Sweden. In Italy, a straight apostrophe ({{code|'}}) is also used in handwriting: "1'234'567,89". In the Netherlands and Dutch-speaking Belgium, points are used as thousands separators, and is preferred for currency values, 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 ({{code|.}}) 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) – 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 commas and points, e.g. "1.234,567.890,12" (or "1.234,567.890·12" in Austo-Hungary and Austria prior to 1938)<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><ref>{{Internet Archive|id=bub_gb_VnswAQAAMAAJ|name=Österreichischer eisenbahnzeitung Zeitschrift des Klub österreichischer eisenbahn un schiffsfahrtbeamten...|page=259}}</ref> for "eine Milliarde 234 Millionen ...", but this isn't seen today and contemporary German readers would require an explanation to understand it.
* In Switzerland, there are two styles. Currency values use an apostrophe ({{code|'}}) as a thousands separator along with a dot ({{code|.}}) as the decimal separator, like "1'234'567.89". For other values, the SI-style "{{gaps|1|234|567,89}}" is used, with a comma ({{code|,}}) as the decimal separator. The apostrophe is also the most common thousands separator for non-currency values, like "1'234'567,89".
* In Ireland, Israel, Japan, [[Korea]] (both), Malaysia, the Philippines, Singapore, Taiwan, Thailand, the United Kingdom, and the United States, "1,234,567.89" or "1,234,567·89" are seen. However, the latter is generally only found in older, [[Manuscript|handwritten]] documents. 
* For English-speaking regions of Canada, there are two styles. The preferred style for currency values is "$10,000.00", while the preferred style for numeric values is "{{gaps|1|234|567.89}}". However, commas are also sometimes used, despite no longer being taught in school or used in official publications.{{Citation needed|date=September 2016}}
* The [[International System of Units]] (SI) uses the following two styles: "{{gaps|1|234|567.89}}" and "{{gaps|1|234|567,89}}". In their own publications, a dot ({{code|.}}) is used in the English version, while a comma ({{code|,}}) is used in the official French version.
* In [[Sweden]], a colon ({{code|:}}) is sometimes used as the decimal separator for currency values, like "{{nobr|1 234 567:89}}".
* In China, commas and spaces are used to mark digit groups, since dots are used as decimal separators. There is no universal convention on digit grouping, however, so both thousands grouping and no digit grouping can be found. Japan and Taiwan are similar, although, when grouping by myriads, [[kanji|{{translit|ja|kanji}}]] or [[Chinese characters]] are frequently used as separators, like the following: "1億2345万6789" or "1億2345萬6789" {{crossreference|(see [[Japanese numerals]] and [[Chinese numerals]])}}. Commas are used when grouping by thousands.
* In [[India]], which uses the [[Indian numbering system]], commas ({{code|,}}) are used at the thousands, [[lakh|{{translit|hi|lakh}}]], and [[crore|{{translit|hi|crore}}]] levels. For example, {{nobr|10 million}} ({{nobr|1 {{translit|hi|crore}}}}) would be written "1,00,00,000", while {{nobr|100 thousand}} ({{nobr|1 {{translit|hi|lakh}}}}) would be written "1,00,000". In [[Pakistan]], there is a greater tendency to use the standard western system, but the Indian numbering system is used when conducting business in [[Urdu]].

{|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;" | 1,000
| Thousand
|-
| scope="row" | {{translit|hi|Lakh}}
| style="text-align: right;" | 1,00,000
| One hundred thousand
|-
| scope="row" | {{translit|hi|Crore}}
| style="text-align: right;" | 1,00,00,000
| Ten million
|-
| scope="row" | {{translit|hi|Arab}} (not normally used)
| style="text-align: right;" | 1,00,00,00,000
| One billion
|-
| scope="row" | {{translit|hi|Kharab}} (not normally used)
| style="text-align: right;" | 1,00,00,00,00,000
| One hundred billion
|-
| scope="row" | {{translit|hi|Lakh crore}}
| style="text-align: right;" | 10,00,00,00,00,000
| One trillion
|}
{{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=}}
* {{unichar|005F|LOW LINE|html=}} - [[Underscore]]

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]]''
* ''[[Rasm]]''
* [[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]]