HTML font size

Root element

The root element of an HTML document is the html element. The font size of this element is set by the browser's default font size setting.

The browser's font size settings is also used as the font size of the medium absolute font size.

Font size, like other text properties are inherited from parent elements.


  • em: N em = N times the font size.
  • rem: N rem = N times font size of root element.

Test yourself

What will the font size of the elements be with this CSS snippet:

html, body { font-size: 2em; }


  • html will have font size of 32px (2 times default font size of browser - 16px).
  • body will have font size of 64px (2 times parent font size).