Free CSS Formatter Online
Format messy or minified CSS instantly — runs in your browser, nothing uploaded.
Input CSS
Formatted CSS
CSS Formatting Examples
Minified CSS is hard to read; formatting adds indentation and line breaks. Example:
Container and button styles
Minified input:
Formatted output:
Click Sample above to load minified CSS into the editor.
What Is a CSS Formatter?
You copy a stylesheet out of DevTools or get a minified CSS file from a build — and it's one solid wall of text. No line breaks, no indentation, just a nightmare to read. A CSS formatter fixes that: it parses your CSS and adds proper indentation and line breaks so you can actually see the selectors, properties, and nesting. The MDN CSS reference and W3C CSS spec define the rules the language follows. Whether you're debugging Bootstrap's compiled output, reviewing third-party CSS, or cleaning up a stylesheet before a code review, formatting makes it legible in seconds. Popular tools like Prettier do the same in your editor — this tool does it instantly in the browser, no setup needed. CSS-Tricks has a solid collection of guides on CSS structure and best practices. For browser compatibility context, Can I Use is the go-to resource.
Paste a stylesheet and it comes back with each rule broken onto its own lines and every declaration indented the same way. The formatting happens on this page rather than on a server, so pasting a production stylesheet is fine. For minifying CSS, use the CSS Minifier. For validation, use the CSS Validator.
How to Use This Tool
Paste or Upload
Copy your CSS and paste it into the left editor. You can also click Upload to load a .css file. The Sample button loads example data. Invalid CSS will show an error.
Check the Output
The right panel updates automatically. Valid CSS gets formatted with proper indentation. Use Minify to remove whitespace and get a compact version for production.
Copy or Download
The tidied CSS goes to your clipboard via Copy, and Download saves it as formatted.css. Working from SCSS or Less? Compile it first: SCSS goes through SCSS to CSS, Less through Less to CSS.
How the Formatter Works
Under the hood the stylesheet is split into selectors, declarations and rule blocks, then printed back out with uniform indentation, with braces and semicolons kept in place. The W3C CSS specifications define the language. Formatting adds line breaks and spaces for readability without changing behavior. At-rules like @media, @keyframes, and @import are handled. None of that work leaves your browser.
Build tools like Vite, Webpack, or Parcel often output minified CSS. Pasting that output here makes it readable. If what you have is preprocessor source, compile SCSS with SCSS to CSS and Less with Less to CSS, then bring the result back here.
When CSS Formatting Helps
Most developers need a formatter when inspecting styles from production sites, debugging third-party CSS, or reviewing minified output from build tools. Pasting compressed CSS here makes selectors and rules visible immediately. Bootstrap or Tailwind compiled output is often minified—formatting reveals the structure. You can use Claude or ChatGPT to generate CSS for complex layouts, then format the output here for readability.
Formatting also helps before sharing styles with teammates or reviewing pull requests. For adding vendor prefixes, use the CSS Prefixer. For converting to inline styles (e.g., for email), use CSS to Inline. For validation, use CSS Validator.
Frequently Asked Questions
Can I paste a production stylesheet here safely?
Yes. The CSS is reformatted by script running on this page and is never posted to a server. If you want proof, keep the Network panel in DevTools open while you paste a stylesheet.
Does it support SCSS or Less?
Only plain CSS. Nesting, mixins and variables from a preprocessor have to be compiled away first (SCSS via SCSS to CSS, Less via Less to CSS), and the compiled output can then be tidied here.
What does Minify do?
It removes whitespace, newlines, and comments from the formatted output, giving you the smallest version for production. There's also a dedicated CSS Minifier page.
Does it preserve comments?
Formatting preserves comments. Minifying may remove them depending on the minifier. Check the output before using in production.
What about CSS custom properties?
CSS variables (--var-name) are supported. The formatter handles modern CSS syntax including custom properties, @media, and @keyframes.