CSS Minifier

The CSS Minifier is an essential free online tool for front-end developers, web designers, and performance engineers who need to compress and optimize CSS files instantly in the browser. During development, CSS files contain extensive indentation, line breaks, whitespace, and comments (/* ... */) for readability, but these are unnecessary for browser rendering and needlessly increase file size.

Simply paste your CSS code and the tool automatically applies a comprehensive set of optimizations to minimize file size:

[Comment, Whitespace & Semicolon Removal] Complete removal of block comments (/* ... */), collapsing consecutive whitespace, line breaks, and tabs, removing unnecessary whitespace around selectors, properties, and values, and stripping trailing semicolons before closing braces (}).

[Advanced Color Compression] Converts rgb() color values to hex notation, then further compresses hex colors (#ffffff → #fff). Uses modern CSS minification techniques to extract additional savings from color declarations.

[Value Normalization] Merges redundant shorthand values (margin: 0 0 0 0 → margin: 0) and removes units from zero values (0px → 0).

After minification, the tool displays original size, minified size, saved bytes, and reduction percentage in real time, so you can instantly verify the optimization impact. The tool fully supports modern CSS syntax including @media queries, @keyframes animations, @font-face declarations, CSS variables (custom properties), and nested rules.

String literal content is preserved intact, so content property values and URL references are never broken. All parsing and compression runs entirely in your browser's JavaScript engine — no proprietary design tokens or CSS architecture details in your stylesheets are ever transmitted to any external server.