CSS Minifier & Beautifier
Compress stylesheets with CSSO or make minified CSS readable again — 100% in your browser
How CSS minification works
CSS minification strips every byte the browser does not need: whitespace, comments, final semicolons and redundant units. This tool uses CSSO (CSS Optimizer), which goes further than simple whitespace removal — it performs structural optimization, merging rules with identical selectors, collapsing shorthand properties (margin: 10px 10px 10px 10px becomes margin: 10px) and rewriting colors to their shortest form (#ff0000 becomes red).
Typical savings are 15–40% of the original stylesheet, depending on how much redundancy it contains. Bootstrap's stylesheet, for example, drops from about 195 KB to roughly 160 KB when minified — and hand-written CSS with generous comments and duplicated rules often shrinks considerably more. On top of that, servers gzip or Brotli-compress CSS in transit, so the gzip estimate shown under the output reflects what actually travels over the network.
Beautify mode expands minified CSS back into readable form with one declaration per line and consistent indentation — useful when you need to inspect or edit a production stylesheet whose source you do not have.
❓CSS Minifier FAQ
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