CSS
Minifier
Remove comments, collapse whitespace, and optimize your CSS. Fast, free, and entirely in your browser.
How It Works
Paste CSS
Paste or type your CSS code into the input area.
Minify
Click Minify to remove comments and optimize whitespace.
Copy or Download
Copy the minified code or download it as a .css file.
Minify CSS online to ship smaller stylesheets, reduce render-blocking time, and improve Lighthouse performance scores. ConverterUp's CSS minifier strips whitespace, removes comments, shortens hex colors, merges duplicate rules, and produces a compact output ready to deploy. Front-end developers, theme authors, and WordPress users can paste a stylesheet, copy the minified result, and serve it from their site or CDN. The processing happens entirely in your browser, so internal design systems and client stylesheets are never uploaded to a third party.
Frequently asked questions
How much can CSS usually be reduced?
Expect 20-40 % size reduction on typical stylesheets. Combined with gzip or brotli compression on the server, most sites end up serving CSS under 30 KB even for full design systems.
Are CSS variables and modern features supported?
Yes. Custom properties, calc(), nested at-rules, container queries, and CSS Layers are all preserved. Vendor prefixes are kept untouched so cross-browser compatibility is not affected.
Does it remove unused selectors?
No. The minifier focuses on safe size reduction. Removing unused selectors requires knowing which HTML actually uses them, which only a tool like PurgeCSS can do during build time.
What is the maximum stylesheet size?
Up to 10 MB per file, which covers any realistic design system. Most production stylesheets are under 200 KB before minification.