PX to REM Converter

Convert pixels to rem/em and back for CSS. Free, no sign-up, works in your browser.

Root font size px

px= rem

Convert a whole stylesheet

Ignore values below px

🔒 100% private — processing happens in your browser. Nothing is uploaded.

How to use the px to rem converter

Set the root font size (16 px is the browser default).
Type pixels or rem — the other field updates.
Or paste CSS and click px → rem to convert every value at once (1px borders are left alone).

Using rem units makes text and spacing scale when users raise the browser font size — an accessibility requirement in WCAG. 1rem equals the root (html) font size; em is relative to the parent element instead.