13px to rem

How the conversion works

CSS unit conversions assume a default root font size of 16px (the browser default), where 1rem = 16px and 1em = 16px in a default context. Points use the CSS reference of 96dpi, so 1pt = 1.3333px. That makes 13px equal to 0.8125rem.

The formula is: rem = px ÷ 16.

When to use rem

rem units are relative to the root (html) font size, so sizing fonts and spacing in rem lets the entire layout scale when a user changes their browser’s default text size. That makes rem the recommended unit for accessible, responsive typography.

Quick reference: px to rem