PX to REM Converter
PX → REM
REM → PX
Reference Table
| px | rem | em |
|---|
What is the difference between PX and REM?
REM (root em) is a CSS unit relative to the root element's (html) font size, which defaults to 16px in most browsers. Using rem instead of px for font sizes, spacing, and layout makes designs respect user accessibility preferences — users who increase their browser's default font size will see everything scale proportionally. Pixels are absolute units that don't respond to user preferences. The standard conversion is: rem value = px value ÷ base font size. At the default 16px base: 24px = 1.5rem, 32px = 2rem, 14px = 0.875rem. This tool also includes a reference table of common sizes.
How to Use the PX to REM Converter
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Enter a pixel value to see its rem equivalent, or enter a rem value to see its pixel equivalent.
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Adjust the base font size if your project uses a different root font size (default is 16px).
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Browse the reference table for common pixel-to-rem conversions.
This PX to REM converter runs entirely in your browser — no data is sent to any server. Supports custom base font sizes. Includes a reference table with common design system sizes. Essential for accessible, responsive CSS design.
Frequently Asked Questions
Should I use rem or em for font sizes? Use rem for font sizes and most spacing. rem is relative to the root font size and is consistent throughout the document. em is relative to the parent element's font size, which compounds in nested elements and can cause unexpected results. rem is generally easier to reason about.
What is the base font size? Most browsers default to 16px for the root font size. If your CSS sets html { font-size: 62.5%; } (a common trick), the base becomes 10px, making rem calculations simpler: 1rem = 10px. Adjust this tool's base size to match your project.
Why use rem over px for accessibility? Users with visual impairments or reading difficulties may increase their browser's default font size in accessibility settings. px units ignore this preference. rem and em units scale with the user's preference, making the UI more usable for everyone.
Keywords: px to rem converter, rem to px, pixels to rem, CSS unit converter, font size converter, responsive design, rem calculator