Free Online Pixels to REM

Pixels to rem is a configurable ratio: rem = px ÷ base, where the default base is 16 px (the browser default).

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rem = px ÷ base. At base 16px, 1rem = 16px.

How to Use This Converter

  1. Set the base font size (default 16 px; use 10 for the 62.5% root trick).
  2. Type a value into either the Pixels or REM field.
  3. The other field updates instantly using the chosen base.
  4. Changing the base recomputes the field you last edited.

What Is a Pixels to REM?

rem (root em) is the dominant CSS length unit for accessible, scalable design. 1 rem equals the document's root font size, which is 16 px by default but users can override it in browser settings. Many design systems also use the 'html { font-size: 62.5% }' trick to make 1 rem = 10 px, so the math is easier (24 px = 2.4 rem).

Front-end developers porting a Figma design to CSS, design-system maintainers picking spacing tokens and accessibility auditors checking that text scales with user preferences all live in this conversion. Buttons and inputs typically sit at 1 rem, headings at 1.5–3 rem, and small UI labels at 0.875 rem.

The tool exposes the base so you can match your project. The default is 16; set it to 10 if you've used the 62.5% root trick.

Frequently Asked Questions

What is REM?
REM = root em. Relative to root font size. 1rem = root font size (usually 16px).
Why use REM over px?
REM scales with user font preferences. Better for accessibility. 1rem = 16px at default.
How do I convert 16px to rem?
At 16px base: 16px = 1rem. 24px = 1.5rem. px ÷ base = rem.

Published by the WeGotEveryTool team. We build and test every tool in-house and update pages when the underlying spec, formula, or recommendation changes.

Reviewed: May 2026. Disclaimer: this tool is provided as-is for general informational use. For decisions with material consequences (medical, legal, financial, security) verify results against a qualified professional source.

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