CSS Minifier/Formatter

Minify or Beautify CSS Code

Free online CSS minifier and formatter. Minify CSS code to reduce file size for production, or format (beautify) to improve readability and maintainability. Works entirely in your browser with complete privacy protection.

How to Use

Minify or format CSS in 3 steps:

Step 1: Enter CSS Code
Paste or type CSS code in the input area on the left
Step 2: Choose Processing Method
Click 'Minify' button to optimize for production, or 'Format' button to improve readability
Step 3: Copy Result
Copy the result displayed on the right. When minifying, the reduction percentage is also shown

All processing is performed in your browser. CSS code is not sent to servers.

CSS Minifier/Formatter

CSS Input

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CSS Output

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Use Cases

CSS Minifier/Formatter is useful in various scenarios:

1. Pre-Production Optimization

Minify CSS before deploying to production to reduce file size. Improves page load speed and reduces bandwidth costs. Typically achieves 30-50% size reduction.

2. Improve Readability of Third-Party CSS

Format minified third-party CSS libraries to understand their contents. Makes debugging and customization easier. Convert minified versions of Bootstrap, Tailwind, etc. to readable format.

3. Code Review Preparation

Format minified CSS for easier team review. Improve code quality with consistent formatting and reduce review time.

4. Performance Optimization

Minify large CSS files to improve website performance. Contributes to better Lighthouse scores and Core Web Vitals, positively impacting SEO.

5. Legacy Code Maintenance

Format old CSS files with inconsistent formatting to a unified style. Improves maintainability and makes bugs easier to find.

What is CSS Minification/Formatting?

CSS minification and beautification/formatting are important techniques for code optimization and improved readability.

How CSS Minification Works

CSS minification reduces file size by removing comments, whitespace, line breaks, and unnecessary semicolons. Functionality remains unchanged while only size is minimized. Example: `body { margin: 0; padding: 0; }` → `body{margin:0;padding:0}`. Typically achieves 30-50% size reduction, improving page load speed.

How CSS Formatting Works

CSS formatting adds appropriate line breaks and indentation to minified code to improve readability. Adds line breaks per selector, arranges properties clearly, and applies consistent styling. Makes debugging, maintenance, and code review easier.

Browser-Based Processing Safety

This tool uses JavaScript to process CSS entirely in your browser. Since CSS code is not sent to servers, you can safely process confidential project code. Works offline with complete privacy protection.

Frequently Asked Questions

How much file size reduction can I expect from CSS minification?

Typically 30-50% file size reduction is possible. CSS with more comments and whitespace achieves higher reduction rates. For example, a 100KB CSS file can often be minified to 50-70KB, leading to significant page load speed improvements.

Can I restore minified CSS to its original state?

Minified CSS can be converted to a readable format using the 'Format' button. However, deleted comments and original line break positions cannot be restored. Therefore, it's recommended to always keep a backup of the original file before minification.

Does this tool support Sass/SCSS/Less?

This tool is for standard CSS only. For preprocessor languages like Sass, SCSS, and Less, please compile to CSS first before using. Many preprocessors have minification options (--style compressed, etc.) that you can also consider.

Will CSS functionality be lost?

No, this tool does not modify CSS functionality at all. It only manipulates whitespace, line breaks, and comments, while preserving selectors, properties, and values exactly. Browser rendering results are completely identical before and after minification.

Can it process large CSS files?

As long as your browser has sufficient memory, large files can be processed. Typically, CSS files of several MB work fine. However, very large files (10MB+) may slow down browser performance.

Are source maps generated?

Currently, source map generation is not supported. For professional development environments, we recommend using build tools like Webpack, Gulp, or Grunt with their source map features. This tool is optimal for simple minification and formatting.

Are CSS syntax errors checked?

This tool can detect basic syntax errors but does not provide complete validation. Syntax errors may prevent correct minification or formatting. We recommend checking syntax in advance using tools like the W3C CSS Validator.

Does minified CSS affect SEO?

CSS minification positively impacts SEO by improving page load speed. Google considers page speed as one of its ranking factors, contributing to improved Lighthouse scores and Core Web Vitals. Mobile user experience also improves.