CSS Unit Converter
Convert between CSS units: px, rem, em, %, pt, vh, vw, and more.
About CSS Unit Converter
Convert between CSS units instantly: px, rem, em, %, pt, vw, vh, vmin, vmax, ch, and ex. Configure the base font size (default 16px) and viewport dimensions for accurate vw/vh conversions. Shows all conversions simultaneously when you enter a value. Essential for responsive design, accessible typography, and translating design tokens to CSS.
All processing happens entirely in your browser using modern web APIs. Nothing is uploaded to our servers — your data stays local and private. Free to use forever.
Common use cases
- Converting px values from a Figma design to rem for accessible typography
- Calculating rem values when your base font size is not 16px
- Understanding the equivalent px value of an em or rem in context
- Converting pt values from print stylesheets to px for screen use
- Checking what percentage a pixel value represents relative to a parent container
How it works
rem conversions divide or multiply by the configured base font size (default 16px). em conversions use the parent context font size. % conversions use a configurable parent container width. vw/vh conversions use the configured viewport dimensions. pt conversions use the CSS standard: 1pt = 1.3333...px (96dpi screen, where 1in = 96px and 1pt = 1/72in).