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CSS unit converter

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Text limit: 2000000 characters

This tool never uploads your input.

A spacing token in rem that a mock still shows in px. You assume 16px — or whatever the project actually set on html.

A Figma inspect panel in px, a codebase in rem. This page is arithmetic at an assumed root. It is not a live computed-style debugger.

Physical units are unit converter. Shadows you are about to paste are box shadow.

Root font-size is an assumption

Teams treat 16px = 1rem until a user zooms or html { font-size } changes. em follows the parent, so the same number moves. Viewport units need a real width. Kitchen cm/inch is the general unit converter, not this page.

How to use it

  1. Set the root px your html actually uses.
  2. Convert rem ↔ px (or whatever the form offers).
  3. Remember user font-size settings can still shift rem.

Honest limits

Not Chrome DevTools. Not print pt with a full CSS2.1 appendix. Not a design-token pipeline.

FAQ

Is the root always 16px?

Often, not always. User zoom and html { font-size: 62.5% } change the math. Type the project’s root.

em vs rem?

rem is the root. em is the parent. Nested em compounds; we will not walk your DOM.

vw / vh / container queries?

Only if the form lists them, and even then the viewport is unknown until runtime.

Kilometers and pounds?

Wrong page — use the general unit converter.

Is anything uploaded?

No.

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