File checksum

Three: SHA-1, SHA-256 and SHA-512. SHA-256 is the default. The digest comes from crypto.subtle.digest, the hashing built into your browser and into Node 20 and later, so the same code runs in both. If you need MD5, BLAKE3, CRC32 or anything else, each of those has its own tool on this site.

No, not for security. Practical collision attacks against SHA-1 are public, so an attacker who controls the content can produce two files with the same SHA-1. Pick it only to match a checksum somebody already published in SHA-1, or to talk to a system that accepts nothing else. For anything where the file might have been swapped, use SHA-256 or SHA-512.

No. The file is read in this tab, hashed by your browser in a Web Worker, and never sent anywhere. There are no accounts and no server side to this tool. Turn your network off and it still works, because the whole site is cached after your first visit.

Two lines: the algorithm name, two spaces, your file name, then the digest in lowercase hex on the next line. SHA-1 gives 40 hex characters, SHA-256 gives 64, SHA-512 gives 128. Hex comparison is case insensitive, so a checksum published in uppercase still matches.

Use Checksum verify instead of doing it by eye. You paste the expected value, it hashes your file and prints MATCH or MISMATCH, trimming whitespace and lowercasing both sides first so a byte identical file cannot fail on formatting. It covers md5, sha1, sha256, sha384, sha512 and crc32.

Not with this tool. It takes one file per run, so drop the next one and run it again. The dedicated per algorithm tools, such as SHA-256 hash, accept as many files as you like in one go and return a separate digest for each.