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PX to REM Converter

Sizing in rem lets a layout scale with the reader's own font settings, which matters for accessibility. This converter works in both directions for any root size and prints a quick reference table of the common values.

How to use it

  1. Set the root font size — 16px unless your CSS changes it.
  2. Type a pixel value, or a rem value in the other box.
  3. Use the table for the sizes you reach for most often.

Examples

Questions people ask

What is the difference between rem and em?

A rem is always relative to the root element, so it stays predictable anywhere in the page. An em is relative to the font size of its own parent, which compounds when elements are nested and can produce surprising sizes deep in a tree.

Should I use rem for spacing as well as text?

Often yes. Padding and margins in rem grow with the reader's font size, so a layout with larger text keeps its breathing room. Borders and hairlines usually stay in pixels because they should not scale.

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Updated: 2026-08-07