Convert between all 14 CSS units instantly. Enter px, rem, em, vw, vh, pt, cm, in, or any other unit and see all conversions at once with context-aware relative unit support.
1616px1212pt11pc0.42330.4233cm4.234.23mm0.16670.1667in11rem11em100100%1.111.11vw1.781.78vh1.781.78vmin1.111.11vmax22chCSS units fall into two categories: absolute units that map to a fixed physical or screen size, and relative units that scale based on context like font size or viewport dimensions. Absolute units include px, pt, pc, cm, mm, and in. Relative units include rem (relative to the root font size), em (relative to the parent element font size), % (percentage of parent), vw and vh (viewport width and height), vmin and vmax (smaller or larger of vw and vh), and ch (the width of the zero character in the current font).
Enter a value and select its source unit. The converter immediately shows the equivalent value in all 13 other units. For relative units to calculate correctly, expand the context panel and set your root font size (typically 16px), parent element font size, and viewport dimensions. These defaults match a standard browser environment, so most conversions work without changing them.
This tool is useful when converting a design spec from px to rem for accessibility compliance, checking how a viewport-relative size behaves at a specific screen width, or understanding how em units cascade inside nested elements. Engineers frequently use it when migrating a codebase from px-based layouts to a rem or fluid unit system.