Website Tools

CSS Validator

Check a webpage's CSS (inline and linked stylesheets) for common syntax issues.

Enter a URL below to check its inline and linked CSS for common syntax issues.

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What Is the CSS Validator?

It fetches a page's inline CSS and up to three linked stylesheets and checks them for common syntax problems such as unbalanced braces and deprecated properties.

When to Use It

When styles are not applied and you suspect a syntax error.
When cleaning up an old theme.

How to Use It

Enter the page URL.
Review the issues listed for each stylesheet.

Understanding the Result

An unclosed brace can cause every rule after it to be ignored, so fix those first. Deprecated properties such as old IE filter or behavior rules can usually be removed.

Limitations

Only the first three linked stylesheets (up to 200 KB each) are checked, and it is a practical syntax check rather than a full CSS specification validator. Minified CSS is harder to report precise line numbers for.

Frequently Asked Questions

It checks a page's inline <style> blocks and up to 3 linked stylesheets for unbalanced braces, empty rule blocks, duplicate selectors, and a small set of deprecated or non-standard properties.

This keeps the check fast and lightweight for everyone using the free tool. Most pages have their most important styling in the first few stylesheets loaded.

Not necessarily - repeated selectors are sometimes intentional (e.g. for media queries). But unintentional duplicates are a common source of confusing, hard-to-debug styling conflicts, so this tool flags them for your review.