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File Entropy Analyzer

Map the entropy of any file to spot encrypted, compressed or hidden regions, with a byte histogram.

Free, no uploads, no sign-up. Runs 100% in your browser.

How File Entropy Analyzer works

Everything happens in your browser with the Web Crypto API and plain JavaScript. Nothing is uploaded, so the files and passwords never leave this device. The file is cut into about 400 blocks and the Shannon entropy of each block is drawn as a chart.

Input: Any file. Output: CSV.

How to use File Entropy Analyzer

1. Drop any file.
2. Hover the chart to read each block.
3. Check the byte histogram and byte types.
4. Download the block data as CSV.

Tips

• Nothing is uploaded, so you can use these tools on sensitive files.
• Share passwords a different way than the file itself.
• Always check a cleaned or redacted file before you send it.

File Entropy Analyzer FAQ

Are my files uploaded?

No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.

Is it free? Are there limits or watermarks?

Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.

Does it work offline?

Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

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• Metadata Scrubber: Remove hidden data from photos, PDFs, Office files and MP3s in one batch: GPS, camera, author, company and more.