Checksums
Checksums for any number of files, in several algorithms at once, and which files are the same. Nothing is uploaded.
Runs in your browser. Nothing is uploaded.
A checksum is how you know a download arrived intact and how you know two files are the same file. Drop in as many as you like, pick one algorithm or six, and every file is read and digested in a worker so the tab stays usable while a large one is going through.
Files that produce the same digest are flagged as duplicates, which turns a folder of downloads into an answer about which copies you can delete. Because the comparison is on the digest rather than the name, a file renamed twice is still caught.
Twenty-eight algorithms are available, grouped by family: SHA-2 and SHA-3 for anything that matters, BLAKE for speed, and the legacy and non-cryptographic ones marked as such — MD5 and CRC32 are still what a lot of software prints, and this will match them, but neither should be trusted against someone deliberately trying to collide them.
Step by step
- 1Choose the algorithms you need — SHA-256 is the usual answer.
- 2Drop the files in.
- 3Press Analyse, then copy the digest or compare it with the one you were given.
Questions
Which algorithm should I use?
SHA-256 unless something told you otherwise. Use MD5 or CRC32 only to match a checksum some other tool has already printed.
Is there a size limit?
No fixed one. Files are streamed through a worker in chunks rather than loaded whole, so multi-gigabyte files work — they just take a while.
Are my files uploaded?
No. They are read in this tab and nothing is sent anywhere, which is the point: a checksum you have to upload a file to get is not much of a check.