What is a hash?
A hash function turns any data into a short fixed-length fingerprint. The same input always gives the same hash, and changing a single character gives a completely different one. You can't turn a hash back into the original data.
- Verify downloads: compare a file's SHA-256 with the checksum published by its developer to make sure it wasn't corrupted or tampered with. Paste the checksum into “Compare with a checksum”.
- Find duplicates: identical files have identical hashes.
- Development: cache keys, integrity checks and verifying API signatures.
Which hash should I use?
| Algorithm | Size | Use |
|---|---|---|
| MD5 | 128-bit (32 hex) | Legacy checksums. Collisions are easy, so never for security |
| SHA-1 | 160-bit (40 hex) | Still in Git, but retired for security use |
| SHA-256 | 256-bit (64 hex) | Today's standard for checksums, signatures and blockchains |
| SHA-384 / 512 | 384 / 512-bit | When a longer digest is required |
| CRC32 | 32-bit (8 hex) | Error detection in zip and PNG. No security at all |
Never store passwords with plain MD5 or SHA-256. Use a deliberately slow password hash such as bcrypt, scrypt or Argon2.
FAQ
Why is my hash different from another site's?
Almost always the input differs slightly: a trailing newline or space, or text encoded as something other than UTF-8. This tool hashes text as UTF-8.
Is my file uploaded?
No. Files are read and hashed in your browser and never leave your device. Very large files may take a moment depending on your device's memory.