CSS Formatter Online: Beautify Minified and Messy Stylesheets
Minified CSS is unreadable by design. A stylesheet compressed for production — one long line, no spaces, no newlines — is optimal for transfer but useless for debugging, code review, or modification. A CSS formatter (also called a CSS beautifier) reverses that: it takes minified or inconsistently formatted CSS and outputs clean, readable code with consistent indentation and one property per line.
What the formatter does to your CSS
The formatting process works by tokenising the input and rebuilding the output according to consistent rules:
Indentation. Each rule block's declarations are indented by the depth you choose — 2 spaces, 4 spaces, or a tab character. Nested at-rules (like @media blocks containing selectors) indent another level deeper, so the visual hierarchy matches the structural hierarchy.
One declaration per line. Every property-value pair gets its own line. color:#333;font-size:16px;margin:0 becomes three separate, scannable lines.
Newlines between rules. A blank line separates each rule block, making it easy to locate individual selectors when scanning a long stylesheet.
Comment preservation. With the "keep comments" option enabled, block comments are retained and re-indented to match the surrounding code. Useful when you're beautifying a commented source file rather than a stripped production build.
Alphabetical property sorting. Declarations inside each rule are sorted A–Z. This is an optional stylistic convention that makes diffs cleaner and rules easier to scan, matching what tools like CSS Declaration Sorter and some Stylelint configs enforce.
Formatting minified CSS you've received
A common scenario: you've been handed a production stylesheet from a client, a vendor, or a previous developer. It's minified — one line, tens of thousands of characters, completely unnavigable. You need to understand it, modify it, or refactor it. Paste it here, click Format, and you have readable code in under a second.
The same applies to CSS generated by frameworks or tools that don't pretty-print their output. Tailwind's JIT output, compiled Sass, PostCSS transforms — they're all valid CSS that benefits from formatting before you inspect it.
CSS formatters vs. Prettier and editors
Prettier formats CSS files excellently when it's already integrated into your project. VSCode's built-in formatter and the Prettier extension will reformat on save if configured. But you don't always have that setup handy — you're on a different machine, you're reviewing a snippet someone pasted in Slack, or you're working on a project where installing Prettier isn't worth the setup time for a one-off task. This tool requires nothing beyond a browser tab.
For teams that want automated, consistent formatting across all CSS files, Prettier with a .prettierrc config is the right long-term answer. For everything else, this formatter works immediately.
Using the formatter alongside other CSS tools
A common three-step workflow: format first to make the CSS readable, then edit it, then minify for production. The CSS minifier handles the last step. If the file also contains comments you want stripped before formatting — sometimes unminified CSS from third parties includes extensive documentation blocks — run it through remove CSS comments first, then format the cleaner result.
For projects that also involve HTML cleanup, the HTML code cleaner handles the markup side: stripping inline styles, removing script blocks, and prettifying HTML structure — the same philosophy applied to a different language.
At-rules, keyframes, and complex selectors
The formatter handles the full range of CSS syntax. @media queries with multiple conditions, @keyframes with percentage-based steps, @supports feature queries, @font-face declarations, and @layer cascade layers all format correctly. Selectors with combinators (>, ~, +), pseudo-classes, and pseudo-elements are preserved exactly. The formatter never modifies selector logic — it only changes whitespace.
Recovering a minified stylesheet you need to edit
If you've inherited a project where the minified CSS file is the only version available — the original source was never committed to version control, or the developer who built it is gone — this formatter is often the fastest way to get something editable. Paste the minified CSS, click format, and you'll have a readable stylesheet within seconds. It's not identical to the original: comments are gone, variable naming choices may not be evident, and logical groupings are lost. But the code works, and you can read it.
From there, treat the formatted output as your new source file. Add it to version control, document it properly, and set up a build step so you're minifying from source going forward rather than editing the deployed file directly. A formatted CSS file produced by this tool is a better starting point than a single 80 KB line of unreadable selectors.
CSS custom properties and modern syntax
CSS custom properties (variables) defined with --property-name: value and accessed via var() are formatted correctly. Nested CSS (the native nesting syntax introduced in Chrome 112 and now broadly supported) is handled as block structure — each nested rule gets its own indentation level. The color-mix(), clamp(), min(), and max() functions are preserved without modification.
If you find the formatted output looks unexpected — properties on the wrong lines, nested blocks not indenting correctly — it typically means the input CSS has a syntax error that's confusing the parser. Run the formatted output through the W3C CSS validator to identify errors, fix them in the source, and re-format. A valid stylesheet always formats cleanly.