Compress CSS for production or beautify for development — free, instant, browser-based
All /* ... */ comments are stripped. Comments are useful in development but invisible to users and unnecessary in production.
Spaces, tabs, and newlines between selectors, properties, and values are removed. margin: 0px becomes margin:0.
6-digit hex colors that can be shortened are converted: #ffffff → #fff, #aabbcc → #abc.
Removes units from zero values: 0px → 0, 0em → 0. Removes leading zeros: 0.5rem → .5rem.
The last semicolon before a closing } is unnecessary and can be safely removed.
Most CSS files shrink by 20–40% after minification. Combined with gzip compression on the server, total download size reduces by 70–80%.
CSS minification removes all characters that are not required for the CSS to function — whitespace, newlines, comments, and redundant semicolons. A smaller CSS file means faster download, faster parse time, and quicker page render. Google's Core Web Vitals score (which affects SEO ranking) rewards fast-loading pages, so minifying CSS is a standard production optimization. Even a 10 KB saving can noticeably improve Time to First Byte and Largest Contentful Paint metrics.
Yes — functionally identical. Minification never changes selectors, property names, values, or the cascade order. It only removes characters that browsers ignore when parsing CSS: whitespace between tokens, newlines, and /* comments */. The browser renders the page identically from both the original and minified version. Always keep your original source file — only serve the minified version to users.
For automated builds: Webpack — use css-minimizer-webpack-plugin. Vite/Rollup — CSS is minified automatically in production builds. PostCSS — add the cssnano plugin. Gulp/Grunt — use gulp-clean-css. CLI — npx csso input.css -o output.min.css. This online tool is best for one-off files or quick checks.
Minifying removes all formatting for the smallest file size — used in production. Beautifying adds consistent indentation and spacing for human readability — used when editing. A common workflow: write CSS in a readable format, commit the readable version to version control, minify as part of the build/deploy process. Never commit minified CSS as the primary source of truth.
Yes. All processing uses JavaScript running in your browser. No CSS is sent to any server. Your proprietary stylesheets, design tokens, and internal CSS files never leave your device.