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.

Baseline Status: Achieved Widely Available on Jan 29, 2018 (Cross-browser Newly Available since Jul 29, 2015).

Desktop Browser Engine Support

Google Chrome

4

Supported

Mozilla Firefox

3.6

Supported

Apple Safari

5

Supported

Microsoft Edge

12

Supported

Mobile Browser Engine Support

Chrome Android

18

Firefox Android

4

Safari iOS

4

Specifications and References

MDN Browser Compat Data Keys: