How to use Gzip Checker
- Run Lighthouse or PageSpeed on your page, export the JSON, and load it into Gzip Checker.
- Gzip Checker shows the page's transfer sizes, resource breakdown and gzip/Brotli savings from the report.
- Read off the largest resources and compression opportunities; the report never leaves your browser.
About this tool
There is no server behind Gzip Checker. Gzip Checker parses an exported Lighthouse/PageSpeed report locally and pulls out page weight, per-type transfer sizes and compression savings.
Everything is parsed on your device; nothing you load is uploaded. It behaves the same on desktop and mobile, with nothing stored remotely.
Frequently asked questions
What is Gzip Checker for?
Gzip Checker lets you check your input right in the browser, with the result shown instantly and nothing uploaded.
Is Gzip Checker free to use?
Yes — Gzip Checker is completely free, with no usage limits.
Where is my data processed by Gzip Checker?
Entirely in your browser — Gzip Checker keeps your data on your own machine and sends nothing anywhere.
How does Gzip Checker measure size and compression?
Gzip Checker reads the resource-summary, total-byte-weight and uses-text-compression audits from a Lighthouse or PageSpeed JSON report you paste, then shows transfer sizes and gzip/Brotli savings — all parsed locally.
Does Gzip Checker work offline?
Once the page has loaded, Gzip Checker keeps working with no network connection.