Convert rem values to pixels (px) or pixels to rem instantly. Set a custom root font size and click quick examples to fill the input in one step. Everything runs in your browser: no login, no installation.
rem (root em) is always calculated from the font size of the HTML root element. When a user increases their browser's default text size, everything sized in rem: fonts, spacing, layout: scales up with it, so the page grows naturally for people with low vision. Values fixed in px stay put no matter what the user does, which hurts accessibility. That's why many teams size typography and spacing in rem.
Designs usually arrive in px while implementation happens in rem, so you constantly move between the two. This converter handles that round trip in one step.
1rem equals the root font size. Most browsers default to 16px, making 1rem = 16px and 1.5rem = 24px. But a project that changes the root (e.g. `html { font-size: 62.5% }`) can make 1rem equal 10px. For an accurate result, set the converter's root font size to match your actual project setup.
Unlike em, which is relative to the parent and compounds when nested, rem is always relative to the root, so it stays predictable. All conversion runs in your browser and your input is never sent to a server.
What it is, who it's for, how it works and why you'd use it.
Rem to Px Converter is a tool that instantly converts CSS rem values to pixels (px) and back.
It is for front-end developers and UI designers who work with both rem and pixel units in CSS layouts.
Enter a rem or px value and set your root font size; the converted result appears instantly in your browser. Use Swap to flip the direction.
It saves repeated manual calculations when switching between px and rem in responsive design workflows.