📏

CSS Unit Converter

Convert between px, rem, em, vw, vh, %, pt, and cm. Set your base font size and viewport width for accurate responsive design calculations.

Root font size (px)

Parent font size (px)

Viewport width (px)

Viewport height (px)

Quick Reference: CSS Units

Unit	Relative to	Best for
`px`	Screen pixels (absolute)	Borders, shadows, fixed layouts
`rem`	Root element font size	Font sizes, spacing (recommended)
`em`	Parent element font size	Component-relative spacing
`vw`	1% of viewport width	Full-width layouts, fluid type
`vh`	1% of viewport height	Full-height sections, modals
`%`	Parent element dimension	Fluid widths, padding tricks
`pt`	1/72 of an inch (print)	Print stylesheets
`cm`	Centimeters (print)	Print/physical dimensions