The Intl.Locale.prototype.calendar property is an accessor property which returns the type of calendar used in the Locale.


The calendar property returns the part of the Locale that indicates the Locale's calendar era. While most of the world uses the Gregorian calendar, there are several regional calendar eras used around the world. The following table shows all the valid Unicode calendar key strings, along with a description of the calendar era they represent.

Unicode calendar keys

Unicode calendar keys
Calendar key (name) Description
buddhist Thai Buddhist calendar
chinese Traditional Chinese calendar
coptic Coptic calendar
dangi Traditional Korean calendar
ethioaa Ethiopic calendar, Amete Alem (epoch approx. 5493 B.C.E)
ethiopic Ethiopic calendar, Amete Mihret (epoch approx, 8 C.E.)
gregory Gregorian calendar
hebrew Traditional Hebrew calendar
indian Indian calendar
islamic Islamic calendar
islamic-umalqura Islamic calendar, Umm al-Qura
islamic-tbla Islamic calendar, tabular (intercalary years [2,5,7,10,13,16,18,21,24,26,29] - astronomical epoch)
islamic-civil Islamic calendar, tabular (intercalary years [2,5,7,10,13,16,18,21,24,26,29] - civil epoch)
islamic-rgsa Islamic calendar, Saudi Arabia sighting
iso8601 ISO calendar (Gregorian calendar using the ISO 8601 calendar week rules)
japanese Japanese Imperial calendar
persian Persian calendar
roc Republic of China calendar
The islamicc calendar key has been deprecated. Please use islamic-civil.


Civil (algorithmic) Arabic calendar


Adding a calendar in the Locale string

Calendar eras fall under the category of locale key "extension keys". These keys add additional data about the locale, and are added to locale identifiers by using the -u extension. Thus, the calendar era type can be added to the inital locale identifier string that is passed into the Intl.Locale constructor. To add the calendar type, first add the -u extension to the string. Next, add the -ca extension to indicate that you are adding a calendar type. Finally, add the calendar era to the string.

let frBuddhist = new Intl.Locale("fr-FR-u-ca-buddhist");
console.log(frBuddhist.calendar); // Prints "buddhist"

Adding a calendar with a configuration object

The Intl.Locale constructor has an optional configuration object argument, which can contain any of several extension types, including calendars. Set the calendar property of the configuration object to your desired calendar era, and then pass it into the constructor.

let frBuddhist = new Intl.Locale("fr-FR", {calendar: "buddhist"});
console.log(frBuddhist.calendar); // Prints "buddhist"


ECMAScript Internationalization API (ECMA-402)

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
calendarChrome Full support 74Edge Full support 79Firefox Full support 75IE No support NoOpera Full support 62Safari Full support 14WebView Android Full support 74Chrome Android Full support 74Firefox Android No support NoOpera Android Full support 53Safari iOS Full support 14Samsung Internet Android Full support 11.0nodejs Full support 12.0.0
Full support 12.0.0
Notes Before version 13.0.0, only the locale data for en-US is available by default. See the Locale() constructor for more details.


Full support  
Full support
No support  
No support
See implementation notes.
See implementation notes.

See also