This tool computes the BLAKE3 cryptographic hash of any text and shows it live in hexadecimal. BLAKE3 is a modern, very fast hash function designed by the authors of BLAKE2; it is suitable for content addressing, deduplication, integrity checks, and key derivation. The default digest is 256 bits, but because BLAKE3 is an extendable-output function you can also request 128 or 512-bit outputs here.
How it works
BLAKE3 hashes input as a binary Merkle tree. The message is split into 1024-byte chunks, and each chunk is compressed block-by-block (64 bytes at a time) using a 7-round mixing function built from the ChaCha-style g quarter-round. Each chunk produces an 8-word chaining value. Chunk chaining values are then merged pairwise by parent nodes — the left subtree always covers the largest power of two of chunks strictly less than the total — until a single root remains.
The final block (for a single chunk) or the root parent node is compressed with the ROOT flag set. To produce output, BLAKE3 runs that root with an increasing output-block counter, which is what lets it emit any number of bytes (the XOF property). This implementation reproduces that whole tree, so it matches the official test vectors for single-chunk, multi-chunk, and extended outputs.
Example and notes
The empty input hashes to af1349b9f5f9a1a6a0404dea36dcc9499bcb25c9adc112b7cc9a93cae41f3262, and the string abc hashes to 6437b3ac38465133ffb63b75273a8db548c558465d79db03fd359c6cd5bd9d85. These are well-known reference values you can use to confirm any BLAKE3 implementation.
BLAKE3 is a cryptographic hash, so it is collision-resistant and safe for integrity verification — but it is unsalted and very fast, which means it is not suitable for hashing passwords directly. Use a slow, salted password hash such as bcrypt, scrypt, or Argon2 for that. Everything here is computed locally in your browser; nothing is uploaded.