Temporal.PlainTime.prototype.since()

Limited availability

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

The since() method of Temporal.PlainTime instances returns a new Temporal.Duration object representing the duration from another time (in a form convertible by Temporal.PlainTime.from()) to this time. The duration is positive if the other time is before this time, and negative if after.

This method does this - other. To do other - this, use the until() method.

Syntax

js
since(other)
since(other, options)

Parameters

other

A string, an object, or a Temporal.PlainTime instance representing a time to subtract from this time. It is converted to a Temporal.PlainTime object using the same algorithm as Temporal.PlainTime.from().

options Optional

An object containing the options for Temporal.Duration.prototype.round(), which includes largestUnit, roundingIncrement, roundingMode, and smallestUnit. largestUnit and smallestUnit only accept the units: "hours", "minutes", "seconds", "milliseconds", "microseconds", "nanoseconds", or their singular forms. For largestUnit, the default value "auto" means "hours". For smallestUnit, the default value is "nanoseconds".

Return value

A new Temporal.Duration object representing the duration since other to this time. The duration is positive if other is before this time, and negative if after.

Exceptions

RangeError

Thrown if any of the options is invalid.

Examples

Using since()

js
const lunchTime = Temporal.PlainTime.from("12:30:00");
const now = Temporal.Now.plainTimeISO();
const duration = now.since(lunchTime);
console.log(`You had lunch ${duration.toLocaleString("en-US")} ago`);
// Example output: "You had lunch 3 hr, 42 min, 21 sec, 343 ms, 131 μs, 718 ns ago"

const duration2 = now.since(lunchTime, { smallestUnit: "minutes" });
console.log(`You had lunch ${duration2.toLocaleString("en-US")} ago`);
// Example output: "You had lunch 3 hr, 42 min ago"

const duration3 = now.since(lunchTime, {
  largestUnit: "minutes",
  smallestUnit: "minutes",
});
console.log(`You had lunch ${duration3.toLocaleString("en-US")} ago`);
// Example output: "You had lunch 222 min ago"

Rounding the result

By default the fractional part of the smallestUnit is truncated. You can round it up using the roundingIncrement and roundingMode options.

js
const time1 = Temporal.PlainTime.from("12:30:00");
const time2 = Temporal.PlainTime.from("12:30:01");
const duration = time2.since(time1, {
  smallestUnit: "seconds",
  roundingIncrement: 15,
  roundingMode: "ceil",
});
console.log(duration.toString()); // "PT15S"

Specifications

Specification
Temporal
# sec-temporal.plaintime.prototype.since

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
since
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