CSS Minifier and Compressor Online

Use this CSS minifier to quickly minify, compress, and optimize stylesheets. Write, paste or upload your CSS, set compatibility and optimization options, then generate a compact stylesheet ready for production. The tool reduces file size while keeping vendor prefixes and behavior intact.

Core capabilities

  • Minify CSS to remove whitespace and comments
  • Compress CSS to shorten values and merge rules safely
  • Rebase URLs and update paths when requested
  • Preserve vendor prefixes for browser support
  • Run entirely in the browser with no server upload

How to use this CSS compressor

  1. Paste, drag and drop, or open your CSS file in the editor
  2. Set Compatibility for old browsers if you need legacy support
  3. Enable Rebase URLs and set the Base Path when relocating assets
  4. Choose Format Style and Optimize Level for the desired output
  5. Click Minify CSS then preview and download the minified file

Why use a CSS minifier or optimizer?

Minify CSS online to reduce transfer time and speed up rendering. A smaller stylesheet improves time to first paint and reduces layout delay for users and search engines.

Use the CSS compressor for production builds and keep readable source files for development. Adjust compatibility and optimize level to balance size and browser support.

Key differences: original CSS vs minified CSS

  • Original CSS is readable and commented
  • Minified CSS removes comments and compresses spacing to cut bytes
  • Shorthand rules replace verbose properties to save size

Example 1: Basic stylesheet

Original CSS

Copy
0.19 KB
body {
	font-family: "Helvetica Neue", Arial, sans-serif;
	margin: 24px;
	color: #333333;
}
/* button styles */
.btn {
	padding: 12px 24px;
	background-color: #007acc;
	color: #ffffff;
}

Minified CSS

Copy
0.13 KB
body{font-family:"Helvetica Neue",Arial,sans-serif;margin:24px;color:#333}.btn{padding:12px 24px;background-color:#007acc;color:#fff}

Example 2: Advanced stylesheet with media queries and keyframes

Original CSS

Copy
0.52 KB
/* navigation styles */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: #222;
  padding: 10px 20px;
}

.navbar a {
  color: #fff;
  text-decoration: none;
  margin: 0 10px;
}

/* keyframe animation */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.fade-in {
  animation: fadeIn 1s ease-in;
}

/* responsive adjustments */
@media (max-width: 768px) {
  .navbar {
    flex-direction: column;
    text-align: center;
  }
}

Minified CSS

Copy
0.32 KB
.navbar{display:flex;justify-content:space-between;align-items:center;background-color:#222;padding:10px 20px}.navbar a{color:#fff;text-decoration:none;margin:0 10px}@keyframes fadeIn{from{opacity:0}to{opacity:1}}.fade-in{animation:1s ease-in fadeIn}@media (max-width:768px){.navbar{flex-direction:column;text-align:center}}

Customization options

Use these editor options to control compatibility, inlining, URL rebasing, output style, and optimization intensity.

Option Default Description
Compatibility All Choose browser compatibility mode, for example IE6 to IE9 or All
Rebase URLs False Adjust relative URLs inside CSS to match a new base path
Base Path empty Set the path used when rebasing asset URLs
Format Style Minified Choose Minified, Beautified, or Keep Breaks for output
Optimize Level Level 2 Select optimization intensity from Level 0 to Level 2

Best practices

  • Keep original CSS in source control
  • Minify CSS for production only
  • Use source maps when debugging compressed CSS
  • Test styles across browsers after optimization
  • Audit third party styles before aggressive merging
  • Automate minify CSS in your build pipeline

Conclusion

This CSS minifier and compressor reduces stylesheet size and improves page speed. Test the minified output across devices and keep source files for maintenance. Use this tool to minify CSS online and deploy smaller, faster stylesheets or use CSS3 formatter to debug stylesheets.