CSS Minifier

How to Use This CSS Minifier

1. Paste your CSS code into the left input panel labeled "Input CSS". You can paste styles from any source including stylesheets, style tags, or inline styles.

2. Click the "Minify CSS" button to compress your code. The minification happens instantly in your browser.

3. View the minified output in the right panel. The statistics bar above shows the original size, minified size, and percentage saved.

4. Click "Copy Output" to copy the minified CSS to your clipboard, ready to paste into your project.

5. Use the "Clear" button to reset both panels and start with new CSS code.

What is CSS Minification?

CSS minification is the process of removing unnecessary characters from CSS code without changing its functionality or visual output. When developers write CSS, they include whitespace, line breaks, comments, and sometimes redundant syntax to make the code readable and maintainable. While these elements are essential during development, they add unnecessary bytes to the file that browsers must download and parse.

The minification process strips out all of these non-essential characters. Spaces between properties are removed, multiple selectors are placed on single lines, comments are deleted, and in some cases, color values and other properties are shortened to their minimal representations. The result is a much smaller file that functions identically to the original but loads faster.

What Gets Removed During Minification

Whitespace and Indentation: All spaces, tabs, and indentation used for formatting are removed. Browsers do not need this formatting to interpret CSS correctly.

Line Breaks: Newlines between declarations and rules are eliminated, often resulting in the entire stylesheet appearing on a single line.

Comments: Both single-line and multi-line comments (/* */) are stripped out. While comments are valuable during development, they serve no purpose in production code.

Unnecessary Semicolons: The final semicolon before a closing brace is optional in CSS and can be removed to save a character per rule.

Extra Spaces Around Operators: Spaces around colons, semicolons, and braces are removed where they are not syntactically required.

Benefits of Minifying CSS

Faster Page Load Times: Smaller files download faster, especially important for users on slow connections or mobile networks. Every kilobyte matters for first contentful paint.

Reduced Bandwidth Costs: For high-traffic websites, the cumulative bandwidth savings can be substantial, reducing hosting costs and server load.

Improved Performance Scores: Tools like Google PageSpeed Insights and Lighthouse specifically check for minified resources and reward optimized sites with higher scores.

Better User Experience: Faster loading pages lead to lower bounce rates and higher user engagement, which can impact conversion rates and SEO rankings.

Minification Savings Formula

The savings percentage displayed by this tool is calculated using the formula: savings = (1 - minified_size / original_size) * 100. Typical CSS minification achieves 15-40% size reduction depending on the original formatting. Well-commented and properly indented code will show larger savings, while already compact CSS will show smaller improvements.

When combined with Gzip or Brotli compression (configured on your web server), the total transfer size can be reduced by 70-90% compared to the original uncompressed file. Minification and compression work together: minification removes redundancy in the source, while compression algorithms find patterns in the remaining content.

When to Minify CSS

Minification should be part of your production build process. Keep your original, readable CSS files for development and generate minified versions for deployment. Most modern build tools like Webpack, Vite, Gulp, and Parcel include CSS minification as a standard feature. This online tool is perfect for quick minification tasks, testing, or when you need to optimize a single file without setting up a build pipeline.