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Enter a webpage URL to instantly check if GZIP compression is enabled. Estimate compression ratios and file size savings to optimize website performance.
This checks the compression coding observed in this response. Sizes count the response content before and after decoding, excluding headers, transfer framing and other page resources. No coding observed here does not prove compression is always disabled.
Overview
Understand what the tool solves, how it works, and the boundaries of its data.
Enter one complete public HTTP or HTTPS URL to inspect the response produced for that request. The check asks for common content encodings, then treats the response as GZIP-enabled only when the final response’s Content-Encoding header contains gzip. This is a single-response result, not a setting lookup for the whole website: a homepage, stylesheet, script, and API route can receive different treatment.
In HTTP, Accept-Encoding tells a server which encodings the requester can accept; Content-Encoding identifies an encoding applied to the response representation. A response marked br is Brotli, not GZIP, so it does not count as GZIP in this checker even though it is compressed. See the RFC 9110 HTTP Semantics for those header meanings.
When GZIP is detected, the result also shows original size, compressed size, a percentage difference, elapsed time, and the response’s server label when supplied. Original size is counted from the returned text as UTF-8 bytes. Compressed size uses Content-Length when available; in some cases the page estimates it by compressing the text locally. These figures may therefore use different measurement paths.
The displayed percentage follows (original size − compressed size) ÷ original size × 100. For example, 100 KB compared with 70 KB yields 30%. Treat that as a comparison of the displayed values, not a guaranteed saving for every visitor or every asset.
Guide
Follow the workflow and verify inputs and outputs with practical examples.
Include https:// or http:// and the exact path you want to inspect, such as https://example.com/assets/site.css. The tool rejects a URL without a protocol.
“Enabled” means the response header indicated GZIP for this request. “Not enabled” means this check did not see GZIP; inspect whether the response used another encoding or returned a redirect, error, or uncompressed representation before changing server settings.
Check a page and selected public CSS, JavaScript, or data URLs individually. A successful homepage check does not establish that other routes or file types behave the same way.
The size cards appear only when GZIP is detected. Compare similar resources and use the results to decide what to investigate next. The elapsed time covers the check request and result processing; it is not a browser page-load score. For a precise transfer measurement, inspect the same request in a browser’s network panel.
Use cases
See how the tool fits into real work and everyday tasks.
A developer or site operator can check a public URL after changing delivery settings and confirm whether that response now declares GZIP.
Check a page, stylesheet, and script separately to spot a path or resource that may follow a different response policy.
Run the same URL on a test host and production host, then compare the reported status and headers as a starting point for troubleshooting.
Q&A
Find concise answers to common questions and confusing cases.
No. It means this response did not declare GZIP. The server may have sent Brotli or another representation, or compression may vary by path, content, request, or delivery layer.
The original text is counted after it is returned, while compressed size may come from a response header or a local GZIP estimate. Transfer framing, automatic decoding, missing headers, or a changing response can make those values differ from a packet-level measurement.
Check that it is publicly reachable and includes the protocol. Login-protected pages, private network addresses, blocked requests, redirects, and timeouts can prevent an online request from getting the intended response.
Notes
Review scope, result limitations, and important precautions before use.
This result describes one request to one URL. It does not audit every page, prove a site-wide server setting, or rate overall performance.
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