Temporal.Instant.fromEpochMilliseconds()

Limited availability

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

See full compatibility

The Temporal.Instant.fromEpochMilliseconds() static method creates a new Temporal.Instant object from the number of milliseconds since the Unix epoch (midnight at the beginning of January 1, 1970, UTC).

To convert a Date object to a Temporal.Instant object, use Date.prototype.toTemporalInstant() instead.

Syntax

Temporal.Instant.fromEpochMilliseconds(epochMilliseconds)

Parameters

epochMilliseconds: A number representing the number of milliseconds since the Unix epoch. Internally, it is converted to a BigInt and multiplied by 1e6 to get the number of nanoseconds.

Return value

A new Temporal.Instant object representing the instant in time specified by epochMilliseconds.

Exceptions

RangeError

Thrown in one of the following cases:

epochMilliseconds cannot be converted to a BigInt (e.g., not an integer).
epochMilliseconds is not in the representable range, which is ±10⁸ days, or about ±273,972.6 years, from the Unix epoch.

Examples

Using Temporal.Instant.fromEpochMilliseconds()

const instant = Temporal.Instant.fromEpochMilliseconds(0);
console.log(instant.toString()); // 1970-01-01T00:00:00Z
const vostok1Liftoff = Temporal.Instant.fromEpochMilliseconds(-275248380000);
console.log(vostok1Liftoff.toString()); // 1961-04-12T06:07:00Z
const sts1Liftoff = Temporal.Instant.fromEpochMilliseconds(355924804000);
console.log(sts1Liftoff.toString()); // 1981-04-12T12:00:04Z

Specifications

Specification
Temporal # sec-temporal.instant.fromepochmilliseconds

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
`fromEpochMilliseconds`	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

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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.

Temporal.Instant.fromEpochMilliseconds()

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