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CSS Minifier — Compress & Optimize CSS

Minify CSS to reduce file size and improve page load speed — free, instant, no login.

✓ Free✓ No Login✓ Removes Comments✓ Removes Whitespace✓ Shows Size Savings

CSS Input

🗜️ What Gets Removed

✕/* Comments */

✕Extra whitespace

✕Newlines and tabs

✕Spaces around { } : ; ,

✕Last semicolons in blocks

✕Empty rules

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PursTech Pro

File upload, batch minify, API access

Get Pro — $7/mo

📖 How to Use the CSS Minifier

Paste Your CSS

Copy your CSS from your editor or stylesheet and paste it into the input box. Click Load Sample to see an example.

Click Minify

Click the Minify CSS button. Comments, whitespace and unnecessary characters are removed instantly.

Copy or Download

Copy the minified output to clipboard or download directly as styles.min.css. Size saving percentage shown — typically 20–40%.

❓ Frequently Asked Questions

What is the difference between minifying and gzip compression?+

Minification permanently deletes unneeded characters from the file itself; gzip or brotli compress it during transfer and the browser unpacks it. They stack — minify first, then let your server gzip the result. The savings percentage shown here is before gzip.

What is CSS minification?+

CSS minification removes all unnecessary characters from CSS code without changing its functionality — whitespace, comments, newlines and redundant semicolons are stripped. The result is a smaller file that loads faster.

How much smaller will my CSS get?+

Typical CSS files see a 20–40% size reduction after minification. Files with many comments and consistent formatting see the largest improvements.

Does minification change how my CSS works?+

No. Minification is purely cosmetic — it removes whitespace and comments that browsers ignore anyway. The rendered output of your website is identical.

Should I minify CSS in production?+

Yes — always minify CSS for production. Smaller files mean faster downloads, better Core Web Vitals scores, and improved SEO rankings. Most build tools like Webpack, Vite and Parcel do this automatically.

Can I reverse minified CSS?+

Not perfectly — comments and original formatting are lost forever. You should always keep your original unminified source files and minify as a build step.

How CSS Minification Reduces Render-Blocking Bytes & Improves LCP

In browser rendering pipelines, external stylesheets are render-blocking resources: the browser will not paint any pixels to the screen until the CSS Object Model (CSSOM) is downloaded and parsed. Every kilobyte of developer comments, indentation spaces, newlines, and redundant semicolons in a stylesheet directly delays First Contentful Paint (FCP) and Largest Contentful Paint (LCP), particularly on mobile networks.

PursTech's CSS Minifier performs safe lexical token compression in your browser: it strips /* ... */ comment blocks, collapses multi-space runs and line breaks, removes unnecessary whitespace around structural delimiters ({, }, :, ;, ,, >), and strips the trailing semicolon before a closing brace (}). Depending on your commenting style and formatting, minification typically shrinks raw CSS files by 20% to 45% before HTTP gzip or Brotli compression is even applied.

Because all minification happens locally in your browser tab, you can safely compress proprietary stylesheets, design-system tokens, and inline critical CSS snippets in seconds.