Gzip Size Estimator & Compression Calculator
Measure uncompressed vs Gzip/Brotli compressed byte sizes and bandwidth savings directly in your browser.
Batch workspace
Format multiple files locally in one run.
How to use the Gzip Size Estimator
Paste code or file
Paste your raw TEXT text or upload directly.
Configure options
Choose indentation, dialect, or formatting preferences.
Format & export
Click format, then copy, download, or inspect in tree view.
What is a Gzip Size Estimator?
Measure uncompressed vs Gzip/Brotli compressed byte sizes and bandwidth savings directly in your browser. This tool re-indents and organizes code according to standard style conventions while checking for syntax validity. Everything executes 100% inside your browser, guaranteeing zero latency and complete privacy for API keys, user tokens, and confidential database schemas.
Frequently Asked Questions
How does the in-browser Gzip estimation work?
It compresses your input using the browser's native `CompressionStream('gzip')` API to measure the exact byte count.
Why is measuring Gzip size important for web performance?
HTTP transfer size directly impacts First Contentful Paint (FCP) and Largest Contentful Paint (LCP) Core Web Vitals.
Is any part of my payload sent to a server?
No. All compression stream calculations occur 100% locally in your browser memory.
What typical compression savings can I expect on JSON and code?
Text and code payloads typically compress by 60% to 85% due to repeated syntax structures and whitespace patterns.
Can I measure minified vs unminified payloads?
Yes. Paste any unminified code or minified code to compare raw bytes vs transfer bytes.