CSS Unit Converter
Convert between CSS units: px, rem, em, and pt. Set your base font size for accurate conversions.
How to Use
Enter a value, select the source unit, set your base font size if needed, and all equivalent values update in real-time.
Frequently Asked Questions
The base font size (default 16px in browsers) determines rem and em conversions. 1rem = 1 × base font size. Change this if your project uses a different root font size.
rem is relative to the root element's font size, while em is relative to the parent element's font size. rem is more predictable in nested elements.
Use rem for scalable, accessible designs that respect user font size preferences. Use px for fixed elements where exact pixel dimensions matter (borders, shadows).