PX ↔ REM / EM Converter

Convert between pixels, rem and em for CSS, with a customisable root font size and common size presets.

Pixels (px)

Root font size (px)

rem / em1rem

CSS value1rem

Common sizes (16px root)

Ad space — always below the tool, never inside it

How to use px ↔ rem / em converter

1Enter a pixel valueType any pixel size.

2Set the root font sizeDefaults to 16px, the browser default — change it if your site sets a different root size.

3Read the rem/em valueUse it directly in your CSS.

rem is always relative to the root (html) font size; em is relative to the current element's font size, which can compound in nested elements.

rem scales with the user's browser font size settings, making your site more accessible to people who increase their default text size.