File checksum

How it works

1. Add the file. A large one takes a moment; it is being read, not sent.
2. Paste the digest the publisher listed, if you have it.
3. The page says match or no match, rather than leaving you to compare two 64-character strings by eye.
4. You can paste the whole published line — “<hash> filename” — and it will still match.

Frequently asked questions

Why not just compare them myself?

Because that is the comparison people get wrong. Two 64-character hex strings that differ in one character in the middle look identical at a glance, and the whole point of checking is to catch the case where they differ. The page does the comparison and gives you a word.

What does a match prove?

That the file is byte-for-byte the one the digest was made from — so it downloaded intact and was not altered in transit. It does not prove who made it. If the site listing the digest were compromised, both the file and the digest could have been replaced. For that, a signature is the tool, not a hash.

Should I use MD5?

Only when that is what you were given. MD5 is broken against a deliberate collision, so it is no use as a guarantee against tampering, but it is perfectly good at catching a truncated or corrupted download — which is what most published MD5s are actually for.

How big a file can it take?

The free plan allows 20 MB per file, which is small for a disc image. Pro removes that. The hashing itself is done by the browser's own crypto and is fast even on large files.

How is this different from the hash generator?

That one hashes text you type — a password, a string, a token. This one hashes a file and compares it. Same arithmetic, different errand, and mixing them makes both worse.

Are my files uploaded?

No. Everything happens in your browser — the files never leave your computer.