Minify CSS code instantly — paste CSS or upload a .css file. Three minification levels: Basic (strip comments), Medium (collapse whitespace), Advanced (full minification with hex shortener). No upload required, 100% free, fully private. Best free online CSS minifier.
50 MB
Max file size
CSS
File format
100% local
Privacy
~5 seconds
Speed
3 levels
Minification
Free forever
Price
Compress JPG and JPEG images to reduce file size while maintaining quality. Adjustable compression with Basic, Medium, and Advanced levels — all processed locally in your browser.
Compress PNG images to reduce file size while preserving transparency. Adjustable color quantization with Basic, Medium, and Advanced levels — all processed locally in your browser.
Compress JPG, PNG, and WebP images to reduce file size. Each format uses optimized compression — quality-based for JPEG/WebP, color quantization for PNG. All processed locally in your browser.
Compress WebP images to reduce file size while maintaining quality. Adjustable compression with Basic, Medium, and Advanced levels — all processed locally in your browser.
Compress multiple JPG, PNG, and WebP images at once. Each image is optimized individually, then bundled into a single ZIP file for easy download. All processed locally in your browser.
Compress PDF files to reduce file size while maintaining readability. Adjustable compression with Basic, Medium, and Advanced levels — each page is re-encoded to minimize size. All processed locally in your browser.
CSS files often contain comments, unnecessary whitespace, and redundant formatting that inflate their size. The CSS Minifier tool strips away everything your browser does not need to render styles, giving you lean, production-ready CSS in seconds.
Whether you are optimizing a WordPress theme, reducing page load times on a landing page, or cleaning up styles before a deployment, this tool gives you complete control over how aggressively your CSS is compressed. Three distinct minification levels let you choose between preserving readability for development or achieving maximum compression for production.
The tool works with two input modes: paste your CSS code directly or upload a .css file. The gradient slider lets you dial in the perfect level of compression, and the 5-second processing spinner ensures you always see visual feedback. All processing happens locally in your browser — your code never leaves your device, making it safe for proprietary or client CSS.
Pro tip: For maximum compression, set the slider to Advanced and minify your CSS before deploying to production. Keep a copy of the original for development work — the minified version is much harder to read and edit.
Before:
/* Header styles */
.header {
background-color: #ffffff;
padding: 20px;
margin: 0 auto;
}
/* Footer styles */
.footer {
background-color: #222222;
color: #ffffff;
padding: 10px 0;
}After (Medium):
.header{background-color:#ffffff;padding:20px;margin:0 auto}.footer{background-color:#222222;color:#ffffff;padding:10px 0}After (Advanced):
.header{background-color:#fff;padding:20px;margin:0 auto}.footer{background-color:#222;color:#fff;padding:10px 0}Advanced also shortens hex colours, drops zero-unit values (e.g. 0px becomes 0), strips inline zeros, and removes redundant spacing around selectors like +, ~, and >.
Yes. At all three levels (Basic, Medium, Advanced), the tool strips CSS comments (/* ... */) and any single-line comments that may appear in preprocessed CSS. This is essential for reducing file size.
Basic removes comments and empty lines only. Medium removes comments, collapses all whitespace including newlines, and tightens spacing around selectors and CSS properties. Advanced does everything Medium does plus shortens hex colours (#ffffff becomes #fff), strips zeros before decimal values like .5 instead of 0.5, and removes redundant spacing in selectors.
Yes, the tool is fully responsive and works on any modern mobile browser. You can paste CSS code directly or upload .css files from your phone or tablet. The gradient slider works with touch input.
Yes, completely free with no hidden costs, subscriptions, or premium tiers. All three minification levels are available without any payment or registration.
No. Everything runs locally in your browser using client-side JavaScript. Your CSS code never leaves your device, ensuring complete privacy for proprietary or client stylesheets.
The maximum file upload size is 50 MB. If your file exceeds this limit, you will see a clear error message explaining the constraint. For paste mode, there is no hard limit but very large amounts of code may affect performance.
Typical savings range from 20-40% for well-structured CSS. Files with excessive comments, large blocks of whitespace, or deeply nested formatting can see reductions of 50% or more. The tool shows an honest before-and-after comparison.
Yes. The minification engine is designed to be safe — it only removes comments, collapses whitespace around CSS syntax tokens (selectors, properties, values), and shortens hex colours. It does not rename classes, alter property values, or remove any CSS rules. Your stylesheets will render identically after minification.
Absolutely. The Advanced level produces output suitable for production deployment. We recommend keeping a copy of your original CSS for development editing, then running it through this tool before deploying to production servers.
The slider controls the minification level, not a quality threshold like JPEG compression. Red/yellow/green represents the aggressiveness: red area (left) = Advanced (full minification), yellow area (middle) = Medium (balanced), green area (right) = Basic (minimal changes). The current level and a description are displayed below the slider.
Yes. When you upload a .css file, the minified output is saved with the same base name plus .min.css appended (e.g. "styles.min.css"). In paste mode, the file is saved as "minified.css".
Yes. After minification, the output is displayed in a read-only textarea. A "Copy to Clipboard" button lets you copy the content with one click. You can also manually select and copy from the textarea.
The tool works best with standard CSS. SCSS, Less, and other preprocessor syntax that includes variables, nesting, or mixins may not be fully minified because the tool treats these as CSS syntax. For best results, compile your preprocessor files to CSS before minifying.
The 5-second spinner provides consistent visual feedback during processing. Even though the actual CSS minification completes almost instantly, the spinner ensures the user sees a clear transition from input to output. The progress indicator shows the percentage of the spinner duration completed.