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HandfulTools

File Checksum Calculator

Check that a downloaded file — an installer, ISO image or backup — is exactly what the publisher released. Drop the file, paste the published checksum and see instantly whether they match.

Runs in your browser

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How to use

  1. Drop or select the file.
  2. Wait while the checksums are computed locally.
  3. Paste the expected checksum to compare automatically.

How it works

The file is read into memory in your browser and hashed with Web Crypto (SHA family) and an MD5 implementation. It is never uploaded, so even multi-hundred-megabyte files are processed privately; speed depends on your device.

If even one bit of the file differs, the checksum is completely different, which makes checksums a reliable way to detect corrupted or tampered downloads.

Examples

Linux ISO
Distributions publish SHA-256 sums next to downloads. Paste it and the tool shows “Match” when the file is intact.

Common uses

  • Verifying software and OS downloads
  • Checking backup integrity
  • Detecting duplicate files

Privacy & security

This tool runs entirely in your browser. Your files and text are never uploaded to our servers — processing happens on your device and results are created locally. How each tool handles files

Frequently asked questions

Is the file uploaded?

No. It is read and hashed inside your browser.

What's the maximum size?

Up to 500 MB, depending on your device's memory.

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