Minify and beautify CSS with smart optimizations. Free, private, runs in your browser.
100% private — your files never leave your browser. All processing happens locally on your device.
CSS minification reduces stylesheet file size by removing comments, collapsing whitespace, shortening color values (#ffffff → #fff), merging shorthand properties (margin-top + margin-right + margin-bottom + margin-left → margin), removing duplicate rules, and eliminating empty rulesets. These optimizations preserve the exact same visual appearance while reducing the bytes that browsers need to download and parse.
CSS is a render-blocking resource — browsers cannot display content until all CSS is downloaded and parsed. Every millisecond spent downloading CSS delays the first paint of your page. Minified CSS loads faster, improving Core Web Vitals scores (especially First Contentful Paint and Largest Contentful Paint). For sites with large stylesheets, minification can save tens of kilobytes, making a noticeable difference in perceived load time.
The tool uses clean-css, the most widely-used CSS optimizer (used by hundreds of thousands of projects). It offers three compression levels: Light (whitespace and comments only), Standard (plus shorthand optimization and color shortening), and Aggressive (plus rule merging, duplicate removal, and advanced restructuring). A Beautify mode is also available to expand minified CSS into readable, properly indented code.
Yes. Your CSS is processed entirely in your browser. No stylesheets are uploaded to any server. This is safe for proprietary design systems, internal stylesheets, and any CSS you want to keep private.
Comment removal, whitespace compression, shorthand property merging (margin, padding), color optimization (#ffffff → #fff), duplicate rule removal, and empty rule removal.
Yes. Switch to Beautify mode to expand minified CSS into properly indented, readable code.
Light (whitespace and comments only), Standard (plus shorthand optimization), and Aggressive (plus advanced merging and restructuring).
Yes. All processing happens in your browser using clean-css. Your stylesheets never leave your device.