CSS Input
Output
Minify CSS to reduce file size, or beautify compressed CSS to make it readable — runs entirely in your browser.
CSS minification reduces stylesheet file size by removing all characters that are not required for correct rendering: whitespace, line breaks, comments, and redundant semicolons. Smaller CSS files load faster, improve Lighthouse scores, and reduce bandwidth costs — especially important on mobile connections. The beautifier does the reverse: it takes minified or poorly formatted CSS and adds consistent indentation, newlines between rules, and clear structure so the code is easy to read and edit. Both operations run entirely in your browser using JavaScript; your code is never uploaded to any server.
For the vast majority of stylesheets, no. This tool removes comments, collapses whitespace, and drops trailing semicolons before closing braces — all of which are safe operations. Edge cases like CSS Hacks using comment syntax (/*\*/) or some IE-specific tricks may not survive minification, but these are rarely used in modern development.
Yes — serving minified CSS is a standard web performance best practice. A stylesheet that compresses from 40 KB to 28 KB saves 12 KB per visitor. At scale, this reduces both server bandwidth and perceived page load time. For development, keep the readable source file; deploy the minified version, ideally also served with gzip or Brotli compression.
They are complementary steps. Minification removes structurally unnecessary characters before the file is sent. Gzip (or Brotli) is HTTP transfer compression that the server applies automatically; the browser decompresses it on arrival. Applying both typically gives the best result: minify first, then let your server gzip the result.