W3cubDocs

Intl.DurationFormat.prototype.format()

Baseline 2025

Newly available

Since ⁨March 2025⁩, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

The format() method of Intl.DurationFormat instances formats a duration according to the locale and formatting options of this Intl.DurationFormat object.

Syntax

format(duration)

Parameters

duration: The duration object to be formatted. It should include some or all of the following properties: years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds. Each property's value should be an integer, and their signs should be consistent. This can be a Temporal.Duration object; see the Temporal.Duration documentation for more information about these properties.

Return value

A string representing the given duration formatted according to the locale and formatting options of this Intl.DurationFormat object.

Note: Most of the time, the formatting returned by format() is consistent. However, the output may vary between implementations, even within the same locale — output variations are by design and allowed by the specification. It may also not be what you expect. For example, the string may use non-breaking spaces or be surrounded by bidirectional control characters. You should not compare the results of format() to hardcoded constants.

Examples

Using format()

The following example shows how to create a Duration formatter using the English language.

const duration = {
  years: 1,
  months: 2,
  weeks: 3,
  days: 3,
  hours: 4,
  minutes: 5,
  seconds: 6,
  milliseconds: 7,
  microseconds: 8,
  nanoseconds: 9,
};

// Without options, style defaults to "short"
new Intl.DurationFormat("en").format(duration);
// "1 yr, 2 mths, 3 wks, 3 days, 4 hr, 5 min, 6 sec, 7 ms, 8 μs, 9 ns"

// With style set to "long"
new Intl.DurationFormat("en", { style: "long" }).format(duration);
// "1 year, 2 months, 3 weeks, 3 days, 4 hours, 5 minutes, 6 seconds, 7 milliseconds, 8 microseconds, 9 nanoseconds"

// With style set to "narrow"
new Intl.DurationFormat("en", { style: "narrow" }).format(duration);
// "1y 2mo 3w 3d 4h 5m 6s 7ms 8μs 9ns"

Using format() with different locales and styles

const duration = {
  hours: 1,
  minutes: 46,
  seconds: 40,
};

// With style set to "long" and locale "fr-FR"
new Intl.DurationFormat("fr-FR", { style: "long" }).format(duration);
// "1 heure, 46 minutes et 40 secondes"

// With style set to "short" and locale set to "en"
new Intl.DurationFormat("en", { style: "short" }).format(duration);
// "1 hr, 46 min and 40 sec"

// With style set to "short" and locale set to "pt"
new Intl.DurationFormat("pt", { style: "narrow" }).format(duration);
// "1 h 46 min 40 s"

// With style set to "digital" and locale set to "en"
new Intl.DurationFormat("en", { style: "digital" }).format(duration);
// "1:46:40"

// With style set to "digital", locale set to "en", and hours set to "long"
new Intl.DurationFormat("en", { style: "digital", hours: "long" }).format(
  duration,
);
// "1 hour, 46:40"

Using format() with the fractionalDigits option

const duration = {
  hours: 11,
  minutes: 30,
  seconds: 12,
  milliseconds: 345,
  microseconds: 600,
};

new Intl.DurationFormat("en", { style: "digital" }).format(duration);
// "11:30:12.3456"

new Intl.DurationFormat("en", { style: "digital", fractionalDigits: 5 }).format(
  duration,
);
// "11:30:12.34560"

new Intl.DurationFormat("en", { style: "digital", fractionalDigits: 3 }).format(
  duration,
);
// "11:30:12.346"

Specifications

Specification
Intl.DurationFormat> # sec-Intl.DurationFormat.prototype.format>

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
`format`	129	129	136	115	16.4	129	136	86	16.4	28.0	129	16.4	1.0.3	1.46	23.0.0