Lighter stylesheets, faster rendering
CSS blocks rendering, so every kilobyte you remove helps pages appear sooner. The minifier (powered by CSSO) strips comments and whitespace, shortens colors and zero values, and goes further than simple whitespace removal by merging duplicate selectors and restructuring rules when it's safe to do so.
Values that are easy to break — calc() expressions, custom properties, grid templates and vendor hacks — are handled correctly. The stats show the original, minified and gzipped sizes so you know what you gained.
How to minify CSS
- 1
Paste your stylesheet
Or open a .css file.
- 2
Choose restructuring
Leave it on for the smallest output.
- 3
Copy or download
Drop the minified CSS into your site.
Key features
Structural optimization
Merges duplicate rules and shorthand properties.
Safe with modern CSS
calc(), variables and grid values stay intact.
Gzip stats
Real-world transfer savings.
No upload
Processed in your browser.
Common uses
- WordPress and theme tweaks: Minify a custom stylesheet before uploading.
- Static sites: Ship production CSS without a bundler.
- Performance audits: Fix “minify CSS” warnings in PageSpeed Insights.
Tips and good to know
- Turn off restructuring if your CSS relies on the exact order of duplicate rules for overrides.
- Need to read the minified file later? Expand it with the CSS Formatter.