CSS Minifier
Compress your stylesheets for faster pages. CSSO removes whitespace and comments, shortens values like #ffffff to #fff and can merge duplicate rules safely.
Runs in your browser — nothing is uploaded Free, no limits
CSS input
Minified
How to use the CSS Minifier
- Paste your CSS, open a .css file or load the sample.
- Leave Restructure on to merge duplicate selectors and declarations, or turn it off for a plain minify.
- Choose whether to keep /*! license */ comments.
- Copy the minified CSS or download it as a .min.css file.
Frequently asked questions
What does CSS minification remove?
Whitespace, line breaks, comments and the last semicolon in each block. It also shortens values, for example 0px becomes 0, #ffffff becomes #fff and redundant shorthand values are collapsed.
What does the Restructure option do?
It lets CSSO merge rules with the same selector or the same declarations and remove overridden properties. It's designed to be safe, but if you rely on unusual cascade order, turn it off to only strip whitespace and shorten values.
Will minified CSS look different in the browser?
No. Minification only changes how the CSS is written, not what it means, so pages render the same.
Does it support modern CSS like custom properties and nesting?
Yes. CSSO handles custom properties, media and container queries, @supports and other modern syntax. Values of custom properties are kept as written.
How much smaller will my CSS get?
Typically 15–40% before compression, depending on how much whitespace, commenting and duplication the source has. The gzip figures show the real network transfer size.
Is my CSS uploaded?
No. The minifier runs entirely in your browser.