CSS Formatter

A CSS Formatter (also called a CSS Beautifier or CSS Pretty Printer) takes minified, inline, or inconsistently spaced CSS and reformats it with consistent indentation, line breaks, and spacing to improve readability and maintainability. It is the opposite of a CSS Minifier — a formatter adds structure for developers while a minifier removes it for delivery.

Paste your CSS into the input panel or open a local .css file. Choose your indentation style (2 spaces, 4 spaces, or tab), configure brace and semicolon options, then click Format CSS or enable Live mode. Review the formatted output, inspect the diagnostics panel, and copy or download the result.

Yes. The formatter supports 2-space indentation (the most common web standard), 4-space indentation (common in PHP and Python communities), and tab indentation (preferred by developers who use accessibility tools or want configurable tab-stop widths in their editor). The indent setting applies to all nested blocks including @media, @keyframes, @supports, and other at-rules.

By default the opening brace is placed at the end of the selector line: .selector {. Enabling the opening brace on new line option moves it to the start of the next line in the Allman/BSD brace style: .selector followed by { on its own line. Some teams prefer Allman style for legibility, while most CSS projects use the default K&R style with the brace inline.

When enabled, all CSS declarations within each rule block are sorted alphabetically by property name. Vendor-prefixed properties sort as if the prefix were stripped, so -webkit-transform and -moz-transform sort near transform. Sorted properties help with diff reviews and code reviews but can change visual reading order — review animated or cascade-order-sensitive declarations after sorting.

Yes. Check Remove comments to strip all block comments from the output. Check Preserve /*! comments to keep important comments (those starting with /*!) even when Remove comments is on. Important comments are conventionally used for license headers, build-tool directives, and attribution notices that should not be discarded.

Yes by default. A blank line is inserted after each closing brace at the root level to separate rule blocks visually. You can uncheck Blank line between rules to produce compact but still formatted output without the extra spacing. Nested blocks inside @media or other at-rules are not affected by this setting.

The diagnostics panel checks for: unclosed block comments that would prevent CSS parsing, mismatched brace counts (different numbers of opening and closing braces), duplicate selectors that may indicate copy-paste errors or redundant rules, overuse of !important (more than five occurrences), and possible missing semicolons before closing braces. These are heuristic checks — review findings before making changes.

No. Formatting and validation are separate concerns. The formatter produces consistently structured output from whatever CSS it receives. Syntax errors, invalid property names, unsupported values, and compatibility issues are not detected beyond the basic lint heuristics. Use a dedicated CSS validator such as the W3C CSS Validator or a project linter like Stylelint for comprehensive validation.

Yes. The formatter handles at-rule blocks including @media, @keyframes, @supports, @layer, @font-face, and @import. Nested blocks inside @media rules are indented to the correct depth. @keyframes percentage stops are formatted as regular rule blocks.

Yes. The formatter is designed to take minified CSS — a single long line with no whitespace — and expand it into a readable multi-line form. This is useful for inspecting third-party stylesheets, debugging build output, or reviewing vendor CSS before modifying it.

When Live mode is enabled, the output panel updates automatically on every keystroke in the input. This is useful for rapid iteration but can be slow on very large stylesheets. For large inputs, disable Live mode and click Format CSS explicitly to format only when you are ready.

Yes. Click Open .css to select a local CSS file. The file is read by the browser's FileReader API entirely in memory. No data is sent to any server. This allows you to format private stylesheets, company design systems, or confidential project CSS without any data leaving your device.

The formatter works on plain CSS including the output generated by SASS, LESS, PostCSS, or Tailwind. It does not parse preprocessor-specific syntax such as SASS variables ($var), LESS mixins, or nesting before CSS Nesting support is compiled. For preprocessor source files use a formatter that understands the preprocessor syntax, then use this tool on the compiled CSS output.

CSS Nesting (the native CSS Nesting spec, not SCSS) uses the same brace and selector syntax as regular CSS, so the formatter handles it correctly — each nested rule is indented one additional level inside its parent block. The formatter does not validate whether the nesting syntax is valid in target browsers.

Yes. CSS custom properties (--my-variable: value) are treated as standard declarations and are reformatted like any other property-value pair. The property name and value are preserved exactly. Custom properties in @property rules are also preserved.

Yes. Click Copy CSS to copy the entire formatted output to the clipboard using the Clipboard API. On older browsers a textarea-select fallback is used. The copied text includes trailing newlines consistent with the formatter output.

Yes. Click the download button to save the formatted output as formatted.css. The file is created as a Blob URL in the browser and no server is involved. You can rename the file after downloading.

The recent formatting sessions panel logs up to eight recent formatting operations. Each entry shows the first line of the input and the timestamp. Click any entry to reload that CSS into the input for further editing or reformatting. History is in-memory only and clears when you close or reload the page.

No. Open DevTools Network tab while using the tool. You will see zero outbound requests triggered by formatting. The entire tool is implemented in vanilla JavaScript running in your browser with no external dependencies. Nothing is uploaded.