Unused CSS Extractor - Free Online SEO Tool

The Unused CSS Extractor is a free online tool that helps you identify CSS selectors defined in your stylesheet that are never actually referenced in your HTML markup. Bloated CSS files slow down page rendering and hurt Core Web Vitals scores, so finding and removing dead styles is an essential step in any website performance optimization workflow.

How It Works

Simply paste your CSS Code into the first input box and your corresponding HTML Code into the second box. The tool scans every selector in your stylesheet and cross-checks it against the classes, IDs, and tags present in your HTML, then reports which CSS rules have no matching elements — meaning they are safe candidates for removal.

Key Features

• Instantly compares CSS selectors against HTML markup to flag unused rules
• Works with class selectors, ID selectors, and tag-based rules
• Simple two-field interface — no installation or sign-up required
• Helps reduce CSS file size for faster page loads

Best Practices

For the most accurate results, paste the complete CSS from your production stylesheet along with the full rendered HTML of the page, including any dynamically injected markup, since selectors used only in JavaScript-generated content may otherwise appear unused. Run this check periodically after redesigns or template changes, as leftover CSS from old components is one of the most common causes of stylesheet bloat. Always test your site visually after removing any flagged rules to confirm nothing was tied to conditional states like hover, focus, or print media.

Why It Matters

Removing dead CSS shrinks file size, reduces render-blocking resources, and improves page speed metrics used in SEO ranking factors. The Unused CSS Extractor gives developers and site owners a fast, free way to keep stylesheets lean and maintainable.