Convert between CSS units: px, em, and rem for responsive web design
Converters
PX to EM/REM Converter
How to Use
1Enter the value you want to convert
2Select the unit you're converting from (px, em, or rem)
3Set the base font size (usually 16px)
4Click Calculate to see the equivalent values in all three units
Frequently Asked Questions
em is relative to the parent element's font size, while rem (root em) is relative to the root HTML element's font size. rem is more predictable for consistent sizing.
Most browsers default to 16px, which means 1rem = 16px by default. You can change this in your CSS with html { font-size: ... }.
Use rem for font sizes and spacing to respect user browser preferences. Use px for fixed-size elements like borders or icons that shouldn't scale.