CSS Formatter - CSS Beautifier / Minifier
CSS Formatter is a free, browser-based tool for cleaning up and standardising CSS code. Paste in anything - minified production output, hand-written styles, or a snippet copied from DevTools - and get back consistently formatted CSS in one click.
Unlike basic formatters, this one understands modern CSS: nesting with &, at-rules inside rulesets (@media, @supports, @layer), complex values like multi-stop gradients and named grid lines, and the full range of pseudo-selectors and pseudo-elements. Everything runs locally in your browser - your code never leaves your machine.
Input CSS - 0 chars
Output - Beautify - 0 chars
About CSS Beautifier / Minifier
A CSS Beautifier and Minifier are two tools used in web development to manipulate and optimize Cascading Style Sheets (CSS), which are used to define the visual style and layout of web pages. These tools serve different purposes:
- CSS Beautifier:
- A CSS Beautifier is a tool that takes a CSS code that might be messy, unorganized, or hard to read and reformats it to make it more human-readable and visually appealing.
- It typically adds indentation, spaces, and line breaks to the CSS code to make it easier for developers to understand and work with.
- A beautified CSS code is often easier to maintain, edit, and debug.
- CSS Minifier:
- A CSS Minifier is a tool that takes a CSS code and reduces its file size by removing unnecessary characters, spaces, and line breaks.
- The primary goal of a CSS minifier is to optimize the CSS file for faster loading on web pages, as smaller file sizes lead to quicker downloads and improved website performance.
- Minified CSS may be less human-readable, as it focuses on compactness and efficiency for the browser.
Web developers often use both beautification and minification tools in their workflow. They beautify the CSS code during development to make it more understandable and maintainable, and then they minify the CSS before deploying it to a production website to optimize performance.
What this tool does - and how
The formatter is built around a custom CSS tokeniser and parser written entirely in JavaScript. Rather than relying on a third-party library, the parser builds an explicit token stream and a context stack that tracks whether each token appears at the root level, inside a selector rule block, or inside an at-rule block. This is what allows it to correctly handle colons in @supports (display: grid) - recognising them as part of a condition expression rather than a property separator - while still correctly splitting color: red into a property and value.
The three formatting modes each serve a distinct use case:
| Mode | Output style | Changes values? | Best for |
|---|---|---|---|
| Beautify | Fully indented, one property per line. Supports multi-line values for gradients, grid templates, and other complex properties. | Whitespace only. | Code review, editing, version control diffs, learning. |
| 1 Line / Rule | Each ruleset on one line. Nested blocks are indented by default; enabling Flatten nested blocks collapses everything to a single line per top-level rule. | Whitespace only. | Quick scanning, pasting into DevTools, sharing snippets. |
| Minify | All whitespace and comments stripped. Trailing semicolons before closing braces removed. Smallest possible output. | Whitespace and comments only. | Production deployment, reducing file size, HTTP payloads. |
| Optimise | A value-level pass that runs alongside any formatting mode. Applies safe rewrites - zero units, hex shorthand, named colours, redundant decimals, font-weight keywords, and more. An optional shorthand conversion step combines margin, padding, border-radius, and overflow longhands. | Yes - values are rewritten. Output is functionally identical but the CSS text changes. | Reducing file size without full minification, enforcing consistent value conventions, preparing CSS for production alongside beautify or minify. |
Features
- CSS Nesting
- Full support for the modern nesting spec —
&,& a,&:hover, and at-rules nested inside rulesets all format correctly. - Multi-line Values
- Gradients, grid template columns with named line tokens, and grid-template-areas are expanded across multiple lines for readability.
- Property Sorting
- Alphabetical property ordering with
all,content, anddisplaypinned first. Vendor-prefixed properties sort alongside their unprefixed counterparts. - Roundtrip Safe
- CSS can be minified and then re-beautified without data loss. Missing semicolons before closing braces are restored automatically on beautify.
- Multi-selector Split
- Comma-separated selectors can optionally be split onto individual lines, making grouped rules easier to read and edit independently.
- Browser Only
- Everything runs in your browser. No server, no account, no analytics. The tool works fully offline once the page has loaded.
Frequently Asked Questions
What is a CSS formatter?
A CSS formatter is a tool that automatically re-styles raw CSS code to make it easier to read and maintain. It adds consistent indentation, line breaks, and spacing - turning minified or hand-written CSS into clean, standardised code without changing how the styles actually behave in a browser.
What is the difference between beautify, compact, and minify?
Beautify expands CSS into fully indented, human-readable code with each property on its own line. Compact puts each ruleset onto a single line, keeping the structure scannable without the full verbosity. Minify strips all whitespace, comments, and unnecessary characters to produce the smallest possible file size for production use.
Does this formatter support modern CSS nesting?
Yes. The formatter fully supports the modern CSS nesting specification, including the & nesting selector, nested @media, @supports, @layer, and @container rules inside rulesets. Colons inside @supports conditions are correctly identified and never mistaken for property separators.
What does the Sort properties A–Z option do?
It alphabetically sorts every CSS property inside each ruleset. The all, content, and display properties are pinned to the top in that order since they are foundational declarations. Vendor-prefixed properties (e.g. -webkit-transform) are sorted alongside their unprefixed counterpart rather than grouped at the top. Nested blocks float to the bottom of their parent ruleset.
Will formatting my CSS change how it works?
Beautify and compact modes only change whitespace - they never alter property values, selectors, or declaration order (unless you enable the sort option). Your CSS will behave identically before and after formatting. Minify also only removes whitespace and comments. The sort option does reorder declarations, which is safe in the vast majority of cases but should be reviewed if your code relies on the cascade order of duplicate properties.
Does the formatter handle gradients and grid templates?
Yes. When the multi-line values toggle is on, all gradient functions - linear-gradient, radial-gradient, conic-gradient, and their repeating-* variants - are expanded with each colour stop on its own line. Grid template columns with named line tokens and grid-template-areas with quoted strings are also formatted across multiple lines.
Is my CSS sent to a server?
No. All formatting is performed entirely in your browser using JavaScript. Your CSS code is never transmitted to any server, stored, or logged. The tool works fully offline once the page has loaded.
What does the Flatten nested blocks option do in 1 Line / Rule mode?
By default, 1 Line / Rule keeps nested blocks indented on separate lines while collapsing each ruleset's declarations to a single line. Enabling Flatten nested blocks collapses everything - including nested @media, @supports, and & selectors - onto a single line per top-level rule. This is useful for copying snippets into DevTools or sharing in chat.