CSS minifier
Compress and optimise CSS to cut file size. Runs entirely in your browser.
Runs 100% in your browserHow to minify CSS
- Paste your CSS. Paste the stylesheet you want to shrink.
- Minify. The minified output and the size saved appear instantly.
- Copy or download. Grab the result with Copy or Download.
About CSS minification
Minifying CSS removes everything a browser doesn't need — comments, indentation, trailing semicolons — and merges or shortens declarations where it's safe to do so. Smaller stylesheets download and parse faster, improving Core Web Vitals. Keep your readable source in version control and minify as a build step or before deploying a one-off file.
Frequently asked questions
- It removes comments, whitespace and redundancy, and applies safe structural optimisations (merging rules, shortening values) using the CSSO optimiser, producing a smaller stylesheet that renders identically.
- CSSO applies only safe transformations by default, so the result is equivalent. As always, test in your project after minifying.
- Yes — paste an entire .css file. Everything runs in your browser, so there is no size limit beyond your device's memory.
- No. Minification happens locally in your browser.