Translator: measureInputUsage() method

Limited availability

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

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The measureInputUsage() method of the Translator interface reports how much input quota would be used by a translation operation for a given text input.

Syntax

js
measureInputUsage(input)
measureInputUsage(input, options)

Parameters

input

A string representing the input text you want an input usage measurement for.

options Optional

An object specifying configuration options for the measureInputUsage() operation. Possible values include:

signal

An AbortSignal object instance, which allows the measureInputUsage() operation to be aborted via the associated AbortController.

Return value

A Promise that fulfills with a number specifying the inputQuota usage of the given input text.

This number is implementation-dependant; if it is less than the inputQuota, the string can be translated.

Exceptions

NotAllowedError DOMException

Thrown if usage of the Translator API is blocked by a translator Permissions-Policy.

NotReadableError DOMException

Thrown if the output translation was filtered by the user agent, for example because it was detected to be harmful, inaccurate, or nonsensical.

UnknownError DOMException

Thrown if the measureInputUsage() call failed for any other reason, or a reason the user agent did not wish to disclose.

Examples

Checking if you have enough quota

In the below snippet, we create a new Translator instance using create(), then return the total input quota via inputQuota and the input quota usage for a translating a particular text string via measureInputUsage().

We then test to see if the individual input usage for that string is greater than the total available quota. If so, we throw an appropriate error; it not, we commence translating the string using translate().

js
const translator = await Translator.create({
  sourceLanguage: "en",
  targetLanguage: "ja",
});

const totalInputQuota = translator.inputQuota;
const inputUsage = await translator.measureInputUsage(myTextString);

if (inputUsage > totalInputQuota) {
  throw new Error("Insufficient quota to translate.");
} else {
  console.log("Quota available to translate.");
  const translation = await translator.translate(myTextString);
  // ...
}

Specifications

Specification
Translator and Language Detector APIs
# dom-translator-measureinputusage

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
Deno
Node.js
measureInputUsage() instance method
Experimental
Chrome – Full support
Chrome 138 (Release date: 2025-06-24)
footnote
footnote Availability may be subject to geographical restrictions.
Edge – No support
Edge
footnote No support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 122 (Release date: 2025-09-11)
footnote
footnote Availability may be subject to geographical restrictions.
Safari – No support
Safari
footnote No support
Chrome Android – No support
Chrome Android
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – No support
Samsung Internet
footnote No support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – No support
WebView on iOS
footnote No support
Deno – No support
Deno
footnote No 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
No support
No support
Experimental. Expect behavior to change in the future.
See implementation notes.

See also