= Locale
{disambiguate=computing}
= Software locale
{synonym}
A <locale (computing)>, also called a <software locale>, identifies a set of language-related and regional conventions used by <software>. Locale-sensitive services use it to select behavior such as date formatting, number formatting or culturally appropriate text ordering. A <locale identifier> can specify a language, script, region and further options.<ICU User Guide by the Unicode Consortium>[Locales and Resources, The Locale Concept and component fields; https://unicode-org.github.io/icu/userguide/locale/]{ref}
An original date example separates meaning from presentation. Let a stored value have year2026, month3 and day4. A day/month/year pattern displays `04/03/2026`, while a month/day/year pattern displays `03/04/2026`. Both represent the same date under their declared patterns. The bare strings do not carry all the information needed to choose the interpretation without context.
A program can pass the selected locale as a parameter to a formatting service instead of hard-coding every convention. Changing that parameter changes the presentation requested for the operation. It does not change the stored date's year, month and day, infer a user's nationality, or convert the character encoding of every string.<ICU User Guide by the Unicode Consortium>[Locales and Resources, Overview and The Locale Concept: locale-parameterized services and user selection]{ref}
The distinction from encoding is especially useful. Two applications can both store text as <UTF-8> while choosing different locale-sensitive display forms. Conversely, two different byte encodings can represent the same textual date. A test record should therefore identify the semantic value, locale selection, format options and relevant library/data version separately.
The <Common Locale Data & Rules> project supplies shared data for such services, and <International Components for Unicode> provides implementations using locale information. A default locale is a convenience for choosing behavior when the application does not supply an explicit choice; making the choice explicit improves reproducibility of an example.<ICU User Guide by the Unicode Consortium>[Locales and Resources, Default Locales and Locales and Services]{ref}
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