GZIP Compression Test - Check Website Compression Free

GZIP Compression Test

Enter a page URL to check whether it is served with GZIP or Brotli compression - and see exactly how many bytes compression saves.

About GZIP Compression Test

What is the GZIP Compression Test?

A GZIP Compression Test checks whether a website compresses its pages before sending them to visitors. GZIP - and its newer sibling Brotli - shrink text-based files like HTML, CSS and JavaScript by 60-80% during transfer. The browser uncompresses them instantly on arrival, so visitors get the identical page in a fraction of the download time. It is one of the highest-impact speed optimizations in existence, yet a surprising number of sites still serve pages uncompressed, wasting bandwidth and testing visitor patience.

The FistHost GZIP Compression Test fetches any URL and inspects its response headers and transfer sizes. It reports the content encoding (gzip, br for Brotli, or none), the original uncompressed size, the actual transferred size, and the exact percentage of bandwidth saved. A green verdict confirms compression is working; an amber warning explains how to enable it on Apache or Nginx. Free, instant, no signup.

How to Use the GZIP Compression Test

1. Enter the URL: Paste the full page address, for example https://example.com.
2. Click Test Compression: The tool fetches the page and analyzes its encoding headers.
3. Read the verdict: Green means GZIP or Brotli is active; amber means the page ships uncompressed.
4. Check the numbers: Compare original versus transferred size and the bandwidth-saved percentage.
5. Fix it if needed: Follow the tip to enable mod_deflate on Apache or the gzip module on Nginx, then retest.

Key Benefits

• Instant diagnosis: Know in seconds whether compression is on or silently missing.
• Real savings shown: Exact byte counts and percentages prove the value to clients and bosses.
• GZIP and Brotli: Detects both classic GZIP and modern Brotli encoding.
• Actionable fix tips: Amber results include concrete server configuration guidance.
• Audit any site: Check your own pages or benchmark competitors.
• Free forever: Unlimited tests with no account.

Pro Tips

• Compress text assets only - HTML, CSS, JS, JSON, XML and SVG. Images and video are already compressed; re-compressing them wastes CPU.
• Prefer Brotli over GZIP when your server supports it - it typically squeezes files 15-20% smaller at the same speed settings.
• Set compression level 6 as a sweet spot; levels 7-9 barely shrink files further but cost noticeably more server CPU.
• Verify compression on both your homepage and asset URLs - servers sometimes compress HTML but forget CSS and JS.
• Combine compression with minification and caching: the three together routinely cut page weight by over 80%.

Frequently Asked Questions

What is GZIP compression?

GZIP is a method servers use to shrink text files before sending them over the network. Browsers decompress the files automatically, so pages load faster while looking identical.

GZIP vs Brotli - which is better?

Brotli is newer and compresses text 15-20% smaller than GZIP. Both are excellent; enable Brotli if your server supports it, otherwise GZIP is still a huge win.

Does compression affect how my page looks?

Not at all. Compression is lossless - the browser reconstructs the exact original file before rendering.

My host says compression is on but the test says no - why?

Some hosts compress only certain file types, or a CDN/proxy strips the encoding. Check the content encoding row and test both www and non-www versions of your URL.

Related Tools

Follow up with our Page Speed Checker for a full performance picture, shrink stylesheets with the CSS Minifier, or audit page links with the Link Analyzer Tool.

Speed starts with the server. FistHost web hosting starts at $0.99/mo with a free domain included - our blazing-fast servers come with compression tuned out of the box, so your pages fly without you touching a config file.