File hash calculator
Check a download against its published checksum. Calculate MD5, SHA-1, SHA-256 and SHA-512 of a file or text. It runs on your device and uploads nothing.
Choose a file to get its checksum, then paste the value the publisher lists to see whether they match. A background worker reads the file in pieces, so even a large download does not freeze the page, and the file never leaves your device.
How it works
- Choose a file, or switch to Text and type something.
- Pick the algorithms to calculate. SHA-256 is the usual choice, and every ticked algorithm is worked out in a single pass.
- Paste the publisher's checksum into the compare box. You see straight away whether it matches.
What happens to your data
- Files are read on your device and never uploaded. Calculating a hash makes no network request.
- Nothing is saved. The result disappears when you choose another file, press Clear or close the tab.
- A background worker reads the file in small pieces, so memory use stays low.
Limits to know about
- MD5 and SHA-1 are no longer collision resistant. They are fine for catching a corrupted download against a value you trust, but not for security.
- A match only shows that the file is the one the checksum was made from. If the checksum came from the same page as a tampered download, it proves nothing, so take it from a source you trust separately.
Frequently asked questions
Which algorithm should I use?
Use whichever the publisher lists. If there is a choice, take SHA-256 or SHA-512. MD5 and SHA-1 still catch accidental damage, but they can be forged on purpose.
Why does my checksum say it is different?
Changing even one byte gives a completely different hash. Check that you compared the same algorithm, that the download finished and that you copied the whole value.
How big a file can it hash?
There is no fixed limit, because the file is read piece by piece. A large file takes longer, and the page shows progress while it works and lets you cancel.