About This Tool
Documentation
What does this tool do?
A comprehensive CSS measurement unit calculator. Convert between absolute (px, pt, pc, in, cm, mm) and relative (rem, em, vw, vh, %) units based on configurable root font size (default 16px) and viewport dimensions (e.g. 1920x1080) with a full 7-unit conversion matrix.
When should you use it?
Use this tool when translating Figma/Sketch pixel specs into accessible REM units, calculating viewport-relative VW/VH container heights, or converting print PT typography into web pixels.
Key Capabilities & Features
Highlights
Instant bidirectional conversion between PX, REM, EM, %, VW, VH, PT, and CM units
Customizable root HTML font-size base (default 16px) with dynamic recalculation
Dynamic viewport dimension simulator calculating real-time VW and VH equivalents
Comprehensive conversion reference table comparing common font sizes and spacing values
One-click copy of calculated values for immediate CSS pasting