CSS Minifier

CSS Minifier - Minify CSS Online

Minify CSS online with CSSO. Paste styles or choose a .css file, then copy or download a separate minified file. Your code stays in your browser.

Only UTF-8 source files are supported. Downloads use UTF-8.

Ready. No code leaves your browser.

The original input is not changed. Review and test the output before publishing.

How to minify CSS online

  1. Add your code

    Paste source text or select a .css file. The file is read locally.

  2. Minify and inspect

    Click Minify CSS. Check any syntax error or inspect the generated code.

  3. Copy or download

    Copy the output or save it as a separate .css file.

Paste CSS or choose a .css file. Click Minify CSS, inspect the output, then copy it or save styles.min.css.

When to use this CSS minifier

Use it to prepare a smaller text asset for a static website, inspect the difference between source and compact code, or create a separate release copy without editing the original.

Limitations

CSSO removes whitespace and applies local CSS optimizations; cross-rule restructuring is disabled. /*! license comments are retained. CSS parsers recover from some malformed but syntactically tolerated declarations; review the output and test your stylesheet in the target browser. The tool does not resolve @import, preprocess Sass/Less, or bundle assets. Large files may briefly occupy the browser main thread. Only UTF-8 source files are supported; downloads are UTF-8.

CSS Minifier FAQ

Is my code uploaded?

No. Selected files and pasted code are processed locally in your browser. Loading the page itself still makes ordinary website requests.

Will it combine selectors across rules?

No. Cross-rule restructuring is disabled. CSSO may still shorten values within individual declarations, so check the resulting styles.

Can I save the original file?

Your original remains untouched; download creates a separate .css copy. Rename it as needed.