Web platform features explorer

rem

The rem CSS length unit is a font-relative length that is equal to the font size of the root HTML element which for most browsers is 16px.

Status

Baseline Widely Available (since 2018-01-29)

MDN documentation

Browser support (view on caniuse.com)

  • Chrome 4 Released on 2010-01-25
  • Chrome Android 18 Released on 2012-06-27
  • Edge 12 Released on 2015-07-29
  • Firefox 3.6 Released on 2010-01-21
  • Firefox for Android 4 Released on 2011-03-29
  • Safari 5 Released on 2010-06-07
  • Safari on iOS 4 Released on 2010-06-21