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Checksum Verifier

Check many downloads against SHA256SUMS or MD5 lists, or make your own checksum file.

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

How Checksum Verifier 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. Files are hashed in 8 MB chunks with hash-wasm, so even large ISO images work. The algorithm is picked from the length of the expected hashes.

Input: Any file, SHA256SUMS, MD5. Output: SHA256SUMS.

How to use Checksum Verifier

1. Drop the files and their checksum list, or paste the expected hash.
2. Leave the algorithm on Auto.
3. Press Verify and read the match column.
4. Or press Calculate and save a new checksum file.

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.

Checksum Verifier 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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