Gzip Size Calculator
Compress text or files with gzip in your browser and compare original size, compressed size, and savings. Private, fast, and free.
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What is Gzip Size Calculator?
A gzip size calculator compresses text and local files with gzip, then reports the original bytes, compressed bytes, and percentage saved. It uses the browser CompressionStream API without sending data to a server.
Key Benefits
- Measure realistic gzip output size
- Estimate bandwidth and storage savings
- Keep private content on your device
- Download a standard gzip stream for testing
Common Use Cases
- •Check API response compression
- •Estimate web asset transfer size
- •Compare text and source-code compression
- •Prepare fixtures for performance testing
How to Calculate Gzip Size
- Enter content: Paste text into the editor or choose a local file to test.
- Start compression: Click Compress Text, or compression starts automatically after choosing a file.
- Review the comparison: Compare the original size, gzipped size, and percentage reduction.
- Download or copy: Download the .gz file for testing or copy the size report to your clipboard.
Key Features
- Compress pasted text with the native browser CompressionStream API
- Compress local files without uploading data
- Compare original and gzipped sizes
- Show the percentage of size reduction
- Download standard .gz output and copy a summary report
Frequently Asked Questions
What does this gzip size calculator measure?
It compresses text or a local file with the browser's gzip implementation and compares the original byte size with the resulting .gz byte size.
Are my files uploaded to a server?
No. Text and files are processed entirely in your browser using CompressionStream, so the input does not leave your device.
Why can gzip make a small file larger?
A gzip file includes headers and metadata. For very small or already-compressed content, that overhead can be larger than the compression savings.
Can I use the result as a production gzip file?
Yes, the downloaded output is a standard gzip stream. It is useful for testing, though web servers should normally handle response compression and headers for you.