Developer Tools
CSS Minifier Online
Reduce unnecessary CSS whitespace for delivery while preserving a readable source file for maintenance.
CSS minification workspace
Process code locally, compare before/after size, then copy, download or continue working with the result.
Input
104 chars
10 lines
Output
0 chars
0 lines
Size change
—
Compared after processing
Privacy
Local browser
Code is not uploaded
Formatting and minification are text transformations, not compilers or runtime validators. Test production output with the relevant browser, build tool or application runtime.
About CSS Minifier
CSS Minifier removes comments, unnecessary whitespace and redundant line breaks from a stylesheet to create a more compact production copy. A smaller CSS response can reduce transfer size and parsing overhead, especially when a project contains several stylesheets. Keep the readable source file in version control and treat the minified output as a generated deployment asset.
Key Features
How to Use
- Paste readable CSS or load the sample.
- Select Minify CSS.
- Review the compact output for unexpected changes.
- Copy or download the result and test it in the target page.
Practical Example
Input
body {
margin: 0;
padding: 0;
background: #ffffff;
}Output
body{margin:0;padding:0;background:#fff}Popular Use Cases
Best Practices
- ✓ Keep the original formatted stylesheet as the source of truth.
- ✓ Test responsive states, pseudo-selectors and media queries after minification.
- ✓ Use build tooling for large production applications with source maps and caching.
- ✓ Measure compressed transfer size because HTTP compression also affects the final payload.
Common Mistakes
- • Editing the minified file directly instead of the readable source.
- • Assuming minification replaces image, font or unused-CSS optimisation.
- • Removing special comments required by a licence or build process.
- • Deploying without checking the result in the browser.
Privacy and Processing
The CSS entered in this page is processed locally in your browser and is not uploaded by the minifier during normal use.
Important limitation: This lightweight utility focuses on common whitespace and comment removal. It does not perform advanced unused-rule analysis, selector rewriting, source-map generation or full build-time optimisation.
Frequently Asked Questions
Does CSS minification change the design?
It should preserve normal CSS behaviour, but always test the final stylesheet because unusual syntax or required comments may need special handling.
Should I replace my source CSS with the minified version?
No. Keep readable source files and generate minified files for deployment.
Does it remove unused CSS?
No. Unused-rule removal requires analysis of your HTML, templates and runtime states.
Will minification improve Core Web Vitals?
It may reduce transfer size slightly, but overall performance also depends on caching, critical CSS, images, fonts and JavaScript.
Can I minify media queries and CSS variables?
Common valid CSS including media queries and custom properties can be compacted, but review the output for project-specific syntax.
Is my stylesheet uploaded?
No. Normal minification runs locally in the browser.