CSS Code Formatter
Free Online CSS Validator & Formatter Tool
Clean, valid CSS is essential for website performance and maintainability. Our all-in-one CSS toolnot only beautifies your stylesheets but also validates them against W3C standards, catching syntax errors and potential issues before they cause problems in production.
Whether you're working with preprocessors like Sass, frameworks like Tailwind, or vanilla CSS, this tool helps you maintain error-free, well-structured code with instant feedback and professional formatting.
How to Validate & Format CSS in 3 Steps
- Paste your CSS – Input any stylesheet (minified, unformatted, or partial code)
- Click "Validate & Format Code" – Get instant validation results and perfectly indented CSS
- Review and fix – Address any warnings or errors highlighted by the validator
Pro Tip: Validate vendor-prefixed properties to ensure cross-browser compatibility.
CSS Validation Features
- Syntax checking – Detect missing braces, semicolons, and invalid properties
- Standard compliance – Validate against W3C CSS specifications
- Error localization – Pinpoint exact line numbers for quick fixes
- Vendor prefix warnings – Identify missing browser prefixes
CSS Formatting Features
- Consistent indentation – 2-space, 4-space, or tab-based formatting options
- Selector organization – Logical grouping of related rules
- Property sorting – Optional alphabetical arrangement of declarations
- Media query nesting – Clear visual hierarchy for responsive styles
Why Validate and Format CSS?
Validation Benefits
- Eliminate rendering inconsistencies across browsers
- Prevent unexpected styling breaks
- Maintain professional code quality standards
Formatting Benefits
- Speed up debugging with clear visual structure
- Simplify team collaboration on shared stylesheets
- Make large CSS files navigable and maintainable
Key Use Cases
- Framework customization – Validate and format Bootstrap/Tailwind overrides
- Legacy code maintenance – Clean up old, messy stylesheets
- Preprocessor output – Check compiled CSS from Sass/Less
- Code reviews – Ensure team styles meet quality standards
- Learning CSS – Get instant feedback on proper syntax