How do I minify CSS online without installing anything?

Paste your CSS into Input CSS, or drop a .css file, then click Minify CSS. Comments and extra whitespace are removed, and you can Copy the result or Download it as styles.min.css.

Does the CSS minifier keep license comments and data URIs intact?

Yes. Regular comments are dropped, but /*! license */ comments are kept. Quoted strings, url() values and data URIs are tokenized separately, so whitespace rules do not alter them.

How do I turn minified CSS back into readable code?

Click Beautify CSS instead of Minify CSS. The code is re-indented with two spaces per level, and selector colons like a:hover are told apart from property colons. Download saves it as styles.css.

What does the gzipped number next to the reduction mean?

It is an estimate of the output size after gzip compression, measured with the browser's CompressionStream API. If your browser lacks that API, the gzipped size is not shown.

Is my CSS sent to a server when I minify it?

No. Minifying is done by a JavaScript tokenizer running in your browser, with no external library. Nothing is uploaded, so you can use it on private stylesheets.

Yes. Every tool is free to use, with no account and no credit card. The work runs on your device rather than on our servers, which is what keeps it free to run.

Does it work on mobile?

Yes. It runs in current mobile browsers on iOS and Android, with nothing to install.

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Free CSS Minifier & Beautifier

Minify CSS to reduce file size or beautify minified CSS for readability. Instant, in your browser.

Runs in your browserNo sign-up, no pop-upsNo login requiredFree forever

Works offline once loaded

or drop a .css file below

Drop a .css file here, or click to browse

CSS · processed on your device

or press Ctrl+V to paste from your clipboard

Browse files

Input CSS

Output CSS

Output will appear here…

Common uses

Minify CSS for Production DeploymentReduce CSS file size before deploying to production — faster page loads and lower bandwidth costs.
Beautify Minified CSS for DebuggingFormat compressed or minified CSS into readable code so you can inspect and debug styles.
Minify CSS for Email TemplatesCompact CSS for HTML email templates where file size and inline style bloat matter.
Minify CSS for WordPress ThemesReduce the size of custom WordPress theme stylesheets for better PageSpeed scores.
Beautify CSS for Code ReviewFormat any CSS file into clean, indented, readable code ready for review and collaboration.

How It Works

This tool uses a hand-written, zero-dependency CSS tokenizer built entirely in JavaScript — no external libraries, no server calls. The tokenizer classifies every character as code, comment, quoted string, or url() value before applying any transformations, which prevents whitespace rules from corrupting string contents, data URIs, or calc() expressions.

1
Tokenization pass
The input CSS is scanned character-by-character and split into typed tokens: raw code segments, /* ... */ comments, quoted strings (preserving escape sequences), and url(...) blocks. This ensures that transformations in the next step only touch actual CSS syntax — never the contents of a string literal or data URI.
2
Minification or beautification
In minify mode, regular comments are dropped (/*! license */ comments are kept), runs of whitespace in code tokens are collapsed to single spaces, and punctuation-adjacent whitespace around { } : ; , > ~ is removed. Spaces around + and - are intentionally left alone to avoid breaking calc() expressions. In beautify mode, the code is first minified to a clean baseline, then re-tokenized and re-indented with two-space depth tracking and declaration-colon detection to distinguish property: value colons from selector colons like a:hover.
3
Gzip size estimate
After producing the output, the browser's native CompressionStream API is used to compress the result with gzip and measure the resulting byte count. This gives a realistic transfer-size estimate matching what a web server with gzip compression would send over the network.
4
Copy or download
The processed CSS is written to the clipboard via the Clipboard API, or downloaded as styles.min.css (minify mode) or styles.css (beautify mode) using a Blob with MIME type text/css. The size reduction percentage is shown live as you type.

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