CSS Minifier
Free CSS Minifier
A CSS minifier is a tool that removes unnecessary whitespace, comments, and redundant code from your CSS to reduce file size. This free online CSS minifier compresses your stylesheet instantly in your browser, with no upload required.
Paste raw CSS or upload a .css file, choose your options, and copy or download the minified result. Safe for production - selectors, properties, !important, and url() values are preserved exactly.
Minified output
How to minify CSS
1
Paste your CSS
Paste raw CSS into the input box, or upload a .css file. The tool accepts any valid CSS - selectors, media queries, keyframes, and at-rules.
2
Choose minification options
Toggle whether to remove comments, drop the last semicolon before a closing brace, and lowercase or shorten hex colors. Defaults are safe for production.
3
Click Minify
Click Minify to compress the stylesheet. The output panel shows the minified CSS along with the original size, minified size, and bytes saved.
4
Copy or download
Use the Copy button to grab the minified CSS, or download it as a .min.css file ready to drop into production.
What this minifier does
Strips comments and whitespace
Removes block comments and collapses every run of spaces, tabs, and newlines that the CSS parser does not need. License headers marked with /*! ... */ are preserved when that option is on.
Trims around safe tokens
Removes whitespace around braces, semicolons, colons, commas, and selector combinators (>, +, ~) only at the top level. Whitespace inside calc(), strings, and url() bodies is preserved.
Shortens hex colors
Lowercases hex colors and rewrites #aabbcc as #abc when the short form is exactly equivalent. 4 and 8 digit hex colors with alpha are lowercased but never shortened.
Frequently Asked Questions
What is a CSS minifier?
A CSS minifier is a tool that removes unnecessary whitespace, comments, line breaks, and redundant code from a stylesheet without changing how it renders. The result is a smaller .css file that downloads and parses faster in the browser.
Why should I minify CSS?
Minified CSS reduces the bytes shipped to every visitor, which improves page load time, Largest Contentful Paint, and Core Web Vitals scores. Smaller files also lower bandwidth costs and parse faster on low-end devices.
Is it safe to minify CSS?
Yes. A correct minifier only strips characters that are not significant to the CSS parser - whitespace, comments, the final semicolon before a closing brace, and equivalent shorter forms of values. Selectors, properties, values, and !important rules are preserved exactly.
Does this tool send my CSS to a server?
No. The NitroClaw CSS minifier runs entirely in your browser using JavaScript. Your stylesheet is never uploaded, logged, or stored on any server, which makes it safe to use with proprietary or unreleased code.
How much can CSS minification reduce file size?
Typical hand-written CSS shrinks by 15-35% after minification, and heavily commented or generated CSS can shrink by 50% or more. Combine minification with gzip or Brotli compression to get the smallest possible payload.
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