SASS Mixin for writing out equivalent font-sizes in px and rem units. Copied from somewhere. Probably Chris Coyler's CSS-Tricks.

_font-size.scss

// Calculate px and rem font-sizes
// - assumes html { font-size: 10px; }
@mixin font-size( $size ) {
	$pixels: #{$size}px;
	$rems:  #{$size/10}rem;
	font-size: $pixels;
	font-size: $rems;
}