Temporal.Duration.prototype.weeks

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

The weeks accessor property of Temporal.Duration instances returns an integer representing the number of weeks in the duration.

Unless the duration is balanced, you cannot assume the range of this value, but you can know its sign by checking the duration's sign property. If it is balanced to a unit above weeks, the weeks absolute value's range depends on the calendar (how many weeks are in a month or year).

The set accessor of weeks is undefined. You cannot change this property directly. Use the with() method to create a new Temporal.Duration object with the desired new value.

Examples

Using weeks

js
const d1 = Temporal.Duration.from({ weeks: 1, days: 1 });
const d2 = Temporal.Duration.from({ weeks: -1, days: -1 });
const d3 = Temporal.Duration.from({ weeks: 1 });
const d4 = Temporal.Duration.from({ days: 7 });

console.log(d1.weeks); // 1
console.log(d2.weeks); // -1
console.log(d3.weeks); // 1
console.log(d4.weeks); // 0

// Balance d4
const d4Balanced = d4.round({
  largestUnit: "weeks",
  relativeTo: Temporal.PlainDate.from("2021-01-01"), // ISO 8601 calendar
});
console.log(d4Balanced.weeks); // 1
console.log(d4Balanced.days); // 0

Specifications

Specification
Temporal
# sec-get-temporal.duration.prototype.weeks

Browser compatibility

desktop mobile server
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Bun
Deno
Node.js
weeks
Chrome – Full support
Chrome 144 (Release date: 2026-01-13)
footnote Full support
Edge – Full support
Edge 144 (Release date: 2026-01-21)
footnote Full support
Firefox – Full support
Firefox 139 (Release date: 2025-05-27)
footnote Full support
Opera – Full support
Opera 128 (Release date: 2026-02-26)
footnote Full support
Safari – Preview support
Safari TP
footnote
footnote See bug 223166
footnote Preview browser support
Chrome Android – Full support
Chrome Android 144 (Release date: 2026-01-13)
footnote Full support
Firefox for Android – Full support
Firefox for Android 139 (Release date: 2025-05-27)
footnote Full support
Opera Android – Full support
Opera Android 95 (Release date: 2026-02-11)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – No support
Samsung Internet
footnote No support
WebView Android – Full support
WebView Android 144 (Release date: 2026-01-13)
footnote Full support
WebView on iOS – No support
WebView on iOS
footnote No support
Bun – No support
Bun
footnote No support
Deno – Full support
Deno 2.7 (Release date: 2026-02-25)
footnote Full support
Node.js – No support
Node.js
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
In development. Supported in a pre-release version.
In development. Supported in a pre-release version.
No support
No support
See implementation notes.

See also