The Intl.Locale.prototype.hourCycle property is an accessor property that returns the time keeping format convention used by the locale.


There are 2 main types of time keeping conventions (clocks) used around the world: the 12 hour clock and the 24 hour clock. The hourCycle property makes it easier for JavaScript programmers to access the clock type used by a particular locale. Like other additional locale data, hour cycle type is an extension subtag, which extends the data contained in a locale string. The hour cycle type can have several different values, which are listed in the table below.

Valid hour cycle types

Hour cycle type Description
h12 Hour system using 1–12; corresponds to 'h' in patterns. The 12 hour clock, with midnight starting at 12:00 am.
h23 Hour system using 0–23; corresponds to 'H' in patterns. The 24 hour clock, with midnight starting at 0:00.
h11 Hour system using 0–11; corresponds to 'K' in patterns. The 12 hour clock, with midnight starting at 0:00 am.
h24 Hour system using 1–24; corresponds to 'k' in pattern. The 24 hour clock, with midnight starting at 24:00.


These examples will show you how to add hour cycle data to your Locale object.

Adding an hour cycle via the locale string

In the Unicode locale string spec, the hour cycle is a locale string "extension subtag". These subtags add additional data about the locale, and are added to locale identifiers by using the -u extension key. Thus, the hour cycle type can be added to the initial locale identifier string that is passed into the Intl.Locale() constructor. To add the hour cycle type, first add the -u extension key to the string. Next, add the -hc extension key to indicate that you are adding an hour cycle. Finally, add the hour cycle type to the string.

const locale = new Intl.Locale("fr-FR-u-hc-h23");
console.log(locale.hourCycle); // Prints "h23"

Adding an hour cycle via the configuration object argument

The Intl.Locale() constructor has an optional configuration object argument, which can contain any of several extension types, including hour cycle types. Set the hourCycle property of the configuration object to your desired hour cycle type, and then pass it into the constructor.

const locale = new Intl.Locale("en-US", { hourCycle: "h12" });
console.log(locale.hourCycle); // Prints "h12"


ECMAScript Internationalization API Specification
# sec-Intl.Locale.prototype.hourCycle

Browser compatibility

BCD tables only load in the browser

See also