What is CSS Unit Converter Online?
Choosing the right CSS unit is critical for accessibility. px is absolute. rem is relative to root font size — essential for accessible typography. em is relative to parent element. % is relative to parent container. Use rem for font sizes so users browser preferences are respected.
How to Use CSS Unit Converter Online
- Set the base font size (default 16px).
- Enter a value in any unit field.
- All equivalent values update instantly.
Frequently Asked Questions
Why use rem instead of px?
rem respects the user's browser font-size preference. If a user sets 20px base size for accessibility, rem-based layouts scale correctly; px stays fixed.