Decimal separator

The decimal separator is a symbol used to mark the border between the integer and the fractional parts of a decimal numeral. This symbol can be a period ("."), as is common in United States and other English-speaking countries, or a comma (","), as in continental Europe and many Arabic-speaking countries (which use a slightly different character ٫ instead). Decimal point and decimal comma are also common names for the decimal separator. For example, 9.5 means nine and one half in English speaking countries, while in many European countries, the same number might be written as 9,5 (and ٩٫٥ in an Arabic-speaking country).

Digit grouping

For ease of reading, numbers with many digits (e.g. numbers over 999) may be put into groups using a delimiter, such as: comma (,), dot (.), half-space or thin space (" "), space (" "), underscore (_), or apostrophe ('). Example, using thin spaces as separator: 20 000 and 1 000 000 for "twenty thousand" and "one million". To stop confusion, different international organizations have called for using spaces, as the digital group separator: ISO, BIPM, IUPAC, and American Medical Association's (AMA).

In many programming languages, digits can be put into groups, to make code easier to read. Ada, D, Fortran, Go, Haskell, Java, JavaScript, Julia, Kotlin, PHP, Python, Rust, Swift, and V (Vlang) use the underscore (_) character for this purpose. The number seven hundred million shows as "700_000_000". In C++ and Red, they use an apostrophe for digit grouping; "700'000'000" in those languages.

Decimal Separator Media

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  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.

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  Three ways to group the number ten thousand with digit group separators: Template:Blist*

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  The interpunct (·) used as a decimal separator in a British print from 1839

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  California milepost marker at mile 144.44

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  Decimal separators:*     Dot (.)*     Comma (,)*     Both (may vary by location or other factors)*     Arabic decimal separator (٫)*     Data unavailable

Related pages

• Arithmetic precision
• Decimal degrees
• Dewey Decimal System