Free Tool

CSS Minifier

Minify CSS code by removing whitespace, comments and unnecessary characters to reduce file size.

Remove comments Collapse whitespace Remove last semicolons Optimize zeros (0px → 0) Shorten hex colors

Drop a .css file here or click to upload

Input CSS 0 bytes

Minified CSS 0 bytes

What Is a CSS Minifier?

A CSS minifier is a tool that compresses CSS (Cascading Style Sheets) files by stripping out everything that isn't required for the browser to interpret the stylesheet correctly. This includes whitespace characters (spaces, tabs, newlines), comments, redundant semicolons, and other unnecessary syntax. The result is a compact, single-line (or near-single-line) file that delivers the same visual result but loads significantly faster.

Modern websites often contain hundreds or thousands of lines of hand-written CSS. While readability is essential during development, production servers benefit enormously from serving minified assets. Smaller file sizes mean faster downloads, lower bandwidth costs, and improved Core Web Vitals scores — all of which directly influence user experience and SEO rankings.

How to Use This Tool

Paste or upload your CSS into the Input field, or drag-and-drop a .css file onto the drop zone.
Choose options — toggle which optimizations to apply: remove comments, collapse whitespace, strip last semicolons before }, shorten 0px to 0, and compress 6-digit hex colors to 3-digit shorthand.
Click Minify CSS to instantly process your code. The minified result appears in the right panel.
Check the size statistics below to see original size, minified size, bytes saved, and percentage reduction.
Copy the result to the clipboard or Download a ready-to-deploy .min.css file.

When Should You Minify CSS?

CSS minification is a standard step in any front-end build workflow. You should minify CSS:

Before deploying to production — always serve minified assets in live environments.
When optimising for PageSpeed / Core Web Vitals — Google's Lighthouse tool explicitly flags render-blocking, unminified CSS.
For email templates — inlined CSS in HTML emails benefits from minification to stay within size limits.
When working without a build tool — if you're not using Webpack, Vite, or Parcel, this tool provides a quick manual alternative.
For third-party stylesheet audits — paste any external stylesheet to see how much it could be reduced.

Frequently Asked Questions

Does minifying CSS break my styles?

No. Minification removes only syntax that browsers ignore — whitespace, comments, and redundant characters. Your selectors, property names, and values are preserved exactly. The output is functionally identical to the input. Always test in a staging environment before deploying to production if you are unsure.

What is the difference between minification and compression?

Minification removes unnecessary characters from the source code itself, producing a smaller plain-text file. Compression (e.g. Gzip or Brotli) is applied by the web server at the HTTP transport level — it encodes the file as binary for transfer and the browser decodes it. Both techniques are complementary; minify first, then let your server compress the minified file for maximum savings.

Will the tool remove important CSS comments like license headers?

With the "Remove comments" option enabled, all CSS comments are stripped, including license or copyright headers. If you need to preserve a specific comment, uncheck that option before minifying, or manually re-add the comment to the output. Many build tools support special /*! syntax to preserve critical comments — this simple tool treats all comments equally.

What does "Remove last semicolons" mean?

CSS rules end with a closing brace }. The semicolon after the last property declaration inside a rule block is technically optional — browsers accept either form. Removing it saves one character per rule block. Across a large stylesheet this can add up to a noticeable saving. The option is safe to enable for all valid CSS.

Is my CSS data sent to any server?

No. This tool runs entirely in your browser using client-side JavaScript. Your CSS code never leaves your device and is never transmitted to any server. This makes it safe to use with proprietary or sensitive stylesheets.

How much file size reduction can I expect?

Typical hand-written CSS files see a 20–40% reduction from minification alone. Files with extensive comments or heavy indentation can achieve 50% or more. Combined with Gzip compression on the server, the total transfer size reduction often exceeds 70–80% compared to the original uncompressed, unminified source.