CSS Minifier — Free Online Tool

The CSS Minifier strips everything a browser does not need in order to apply your styles — comments, indentation, line breaks, the final semicolon in a block, and redundant whitespace around colons and braces — leaving a stylesheet that is byte-for-byte smaller but renders identically. Typical savings on hand-written CSS land somewhere between 20 and 40 percent before compression.

Minification is not the same thing as gzip or Brotli, and the two stack rather than compete. Your server compresses CSS on the way out regardless, but compression works better on shorter input, and the browser still has to parse whatever arrives. On top of that, CSS is render-blocking: the browser will not paint until it has fetched and parsed your stylesheet, which is why stylesheet size shows up directly in First Contentful Paint rather than being hidden the way a late-loading script can be.

The one rule worth respecting is to keep the readable source as the file you actually edit and treat the minified output as a build artefact. Editing minified CSS by hand is miserable, and pasting it back over your source is a mistake people only make once.

Minification runs entirely in your browser, so proprietary stylesheets from a client project are not uploaded anywhere.

Our CSS Minifier is completely free to use with no signup required. For this tool, processing runs in your browser — your files and data stay on your device and are not uploaded to our servers.

Whether you are a developer, designer, student, or business owner, this tool is designed to save you time and make your workflow more efficient. Bookmark this page to access it whenever you need it — it will always be free.