The GZIP Compression Checker is a free online tool that tests whether any website or URL has GZIP compression enabled on its web server. GZIP compresses web resources (HTML, CSS, JavaScript) before sending them to the browser — typically reducing transfer size by 60–80%. This dramatically reduces page load times and bandwidth usage.

Google's PageSpeed Insights flags missing GZIP compression as a high-impact issue. Enabling GZIP is one of the fastest, lowest-effort performance improvements available and is supported by virtually all modern web servers and browsers.

How to Check GZIP Compression

• Enter any URL you want to test
• Click Check GZIP
• The tool sends a request with Accept-Encoding: gzip in the header
• Results show: compression status, original size, compressed size and savings percentage

How to Enable GZIP on Your Server

For Apache (add to .htaccess):

AddOutputFilterByType DEFLATE text/html text/css application/javascript

For Nginx (add to nginx.conf):

gzip on; gzip_types text/html text/css application/javascript;

Results Interpretation

• Compressed ✓ — GZIP is working, no action needed
• Not compressed ✗ — Enable GZIP on your server for instant speed gains

Free, instant GZIP check, no login required.

Want to learn more? Read our complete guide: How to Speed Up Your Website and Improve Core Web Vitals →