BLAKE3 File Hash
Calculate BLAKE3 hashes, keyed hashes, or derived output for local files and accessible URLs in your browser with selectable output length. Read more
What is BLAKE3?
BLAKE3 is a tree-based cryptographic function designed for parallel and incremental processing. This page reads the raw bytes of a local file or accessible URL and supports ordinary Hash, Keyed Hash, and Derive Key modes with configurable output length.
How to use this file hash calculator
Choose a local file or URL, select the BLAKE3 mode, output length, and output encoding, then calculate. Keyed Hash requires exactly 32 key bytes. In Derive Key mode, the Key field supplies the derivation context rather than a secret MAC key.
Local files are processed in your browser and are not uploaded by this tool. URL mode depends on the remote server allowing a browser cross-origin request.
Result example
The filename is not included. Files with identical bytes produce the same ordinary hash regardless of their names, while any changed file byte normally changes the result. Mode, output length, key, and context must also match when comparing non-default output.
Important limitations
An ordinary file digest detects changes only relative to a trusted expected value. Keyed Hash can authenticate data to parties that share the 32-byte secret, but it does not provide public verification like a digital signature. Derive Key should be used only when an application defines the context and source key material; it is not for deriving keys directly from user passwords.
See the official BLAKE3 repository and specification for mode definitions and test vectors. Use the BLAKE3 text calculator when you need to control text encoding before hashing.
Frequently asked questions
Why does my result differ from another tool?
Check the exact file bytes, BLAKE3 mode, output length, key or context, and output encoding. Confirm that the other implementation uses BLAKE3 rather than BLAKE2 or another similarly named function.
Can I use the result to verify a download?
Yes, when the expected BLAKE3 value is obtained independently from a trusted source and all parameters match. If the file and checksum can both be replaced together, an ordinary hash comparison does not prove authenticity.
