Free CSS Formatter Online

What this page is for

Minified CSS is efficient for a browser and painful for a person. A single line can contain hundreds of rules, and a missing brace becomes almost impossible to spot. This page parses the stylesheet, rebuilds the rule tree and prints it with consistent line breaks and indentation so you can read, review or repair it.

The page opens with CSS and Beautify already selected and accepts up to 200,000 characters per run. Processing happens on the server. The output is a formatted stylesheet, not a different stylesheet: the selectors and declarations are meant to survive the pass unchanged.

How the formatter works

The server hands the source to a CSS parser, which builds a tree of rules, at-rules, declarations and comments. The tree is then rendered with a pretty output format. That format puts a newline before and after each rule, separates blocks with a blank line and prints one declaration per line.

The parser indents nested blocks with a tab character by default. If your project uses spaces, the output will not match your style guide, but it will still be readable. Treat this page as a viewer and a repair aid rather than a substitute for the formatter configured in your editor.

What the output looks like

Selectors are separated from the opening brace by a single space character. Declarations are printed one per line with a colon and a space after the property name. Closing braces sit on their own line. At-rules such as @media and @supports receive a block, and the rules inside are indented one level deeper. Comments that the parser recognises are printed as comments.

Long values are not wrapped, so a custom property holding a very long gradient stays on one line. That is normal: CSS has no safe generic line-breaking rule for values.

Which comments survive

Comments at the top level and between rules are printed, so a section banner usually survives the pass. A comment placed inside a declaration block is a different case: testing this page shows that it can be dropped, because the parser treats it as part of the block rather than a standalone node. Keep important notes outside rule blocks if you need them to survive.

Do not rely on beautifying to recover comments from an already-minified file. They were removed by the minifier, and no formatter can bring them back.

What can change in the output

Formatting should not change meaning, but a parser-based pass can normalise small details. Quotes may be standardised, extra whitespace inside values may be collapsed, and empty declarations may disappear. Vendor-specific hacks that are not valid CSS, such as the old star hack or underscore hack, may be rejected by the parser or printed differently.

If a stylesheet depends on those hacks, keep the original. The same applies to files that contain template syntax: a CSS parser does not understand Blade, Twig or JavaScript expressions embedded in property values, and it may fail or produce a broken tree.

Modern CSS and parser support

CSS nesting, @layer, @container and @scope are newer than many PHP CSS parsers. A parser that does not understand nesting may treat the nested block as a syntax error, drop it, or flatten it incorrectly. Check the output for any construct introduced in the last few years before you use it.

If the parse fails, the page returns an error rather than a partial stylesheet. That is safer than silent corruption, but it means a single unsupported rule can block the whole file. In that case, format the file in your editor or split out the unsupported section.

Fetching CSS from a URL

The URL tab downloads a public stylesheet on the server and puts the response in the editor. The fetch is capped at 200,000 characters. CDN links usually work; authenticated links, bot-protected links and signed URLs usually do not. The server fetches the raw response, so an HTML error page will arrive as HTML and fail to parse as CSS.

Step by step

1. Paste the stylesheet into Manual Code, or load it with the URL tab.
2. Confirm the language is CSS and the mode is Beautify.
3. Press Process Code.
4. Read the output from the top: a broken brace is much easier to see once every block is indented.
5. Copy the formatted CSS, or download it as beautify-output.css.
6. Compare the selectors and declarations with the original before replacing anything.

When beautifying helps

It helps when you need to review a vendor stylesheet before overriding it. It helps when a minified file misbehaves and you want to find the rule that wins. It also helps when you are learning CSS and want to see how a real framework organises its selectors.

It is less useful as a commit step. Reformatting an entire file creates a large diff that hides the actual change. If you only need to read the file, beautify a copy and leave the repository version alone.

Checking the result

Compare the number of rules and the number of declarations in the input and output. A sudden drop usually means the parser rejected a construct. Load a page that uses the stylesheet and check layout, colours, fonts and responsive breakpoints. Pay particular attention to hacks, custom properties and anything that uses a preprocessor-style expression.

Reading a vendor stylesheet

When a framework rule overrides yours, the fastest way to find it is to search the formatted file for the selector and read the surrounding block. Minified CSS puts every rule on one line, so a search hit gives you very little context. After beautifying, each selector starts its own line and each declaration sits underneath it, which makes the cascade much easier to follow.

Keep the formatted copy outside your project. Editing a vendor file directly is fragile because the next package update replaces it. Copy the rule you need into your own stylesheet and override it there.

Print and accessibility blocks

Stylesheets often contain @media print, @media (prefers-reduced-motion) and @media (prefers-color-scheme) blocks near the end. These are easy to miss in a minified file and easy to break when a parser does not support the query syntax. After formatting, scan the at-rules and confirm that each block still has its declarations. Then test print preview and the reduced-motion setting if the page supports them.

Limits

One stylesheet per run, 200,000 characters, CSS mode on this page. The code is processed on the server and returned; it is not stored. The tool does not lint, validate, autoprefix or check browser support. It does not guarantee that the output is byte-identical to the input, only that it is intended to be equivalent CSS.

Frequently Asked Questions