On the standards track: Yes
Is Experimental: No
Is Deprecated: No
In Bun version 1.0.0 on 2023-09-08
In Chrome version 71 on 2018-12-04
In Chrome Android version 71 on 2018-12-04
In Deno version 1.8 on 2021-03-02
In Edge version 79 on 2020-01-15
In Firefox version 65 on 2019-01-29
In Firefox for Android version 65 on 2019-01-29
Not in Internet Explorer
In Node.js version 13.0.0 on 2019-10-10 Note: Before version 13.0.0, only the locale data for en-US is available by default. When other locales are specified, the RelativeTimeFormat instance silently falls back to en-US. To make full ICU (locale) data available before version 13, see Node.js documentation on the --with-intl option and how to provide the data.
In Quest Browser version 6.0 on undefined
In Opera version 58 on 2019-01-23
In Opera Android version 50 on 2019-02-18
In Safari version 14 on 2020-09-16
In Safari on iOS version 14 on 2020-09-16
In Samsung Internet version 10.0 on 2019-08-22
In WebView Android version 71 on 2018-12-04
In WebView on iOS version 14 on 2020-09-16