CSS Unit Converter

Convert between CSS units: px, em, rem, vw, and more

Configuration (base sizes)

Root font-size (px)

Parent size (px)

Viewport width (px)

Viewport height (px)

Unit	Value	Description
`px`	16	Pixels — absolute unit, 1/96 of an inch
`em`	1	Relative to parent element's font-size
`rem`	1	Relative to root element's font-size
`%`	100	Relative to parent element
`vw`	1.1111111	1% of viewport width
`vh`	1.7777778	1% of viewport height
`pt`	12	Points — 1/72 of an inch (print)
`cm`	0.42333333	Centimeters
`mm`	4.2333333	Millimeters
`in`	0.16666667	Inches
`pc`	1	Picas — 12 points

Common conversions

How to Use This Tool

Enter your input

Type or paste the value you want to look up or convert into the input field.

Get instant results

Results are computed immediately in your browser — no network request needed.

Use the reference

Browse the built-in reference table to find related values, codes, or descriptions.

Copy what you need

Use the "Copy" button to grab any value from the results for use in your project.

About This Tool

CSS Unit Converter is a free, instant, browser-based tool that convert between css units: px, em, rem, vw, and more. Web developer tools provide quick access to reference data and small utilities that come up constantly during development. HTTP status codes, Unix timestamps, chmod permission calculators, ASCII tables, and similar references are things every web developer looks up regularly. Having them in one place, instantly accessible in your browser, speeds up your workflow significantly.

This tool runs entirely in your browser with no server calls required. Results appear instantly and everything works offline once the page is loaded.

Bookmark this page for quick access during development sessions. Whether you're debugging a 403 vs 401 response, converting a timestamp from a database field, setting file permissions on a Linux server, or checking what ASCII character code 127 corresponds to, having a reliable, distraction-free reference tool cuts down the time you spend looking things up and lets you stay focused on the problem at hand.

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