SHA-3 (Keccak) Hash Generator
Calculate a real SHA-3 hash, live as you type — hand-implemented from the Keccak specification, since Web Crypto doesn't support SHA-3.
About this tool
SHA-3 (based on the Keccak algorithm) uses a fundamentally different internal structure from SHA-2 — a "sponge" construction rather than the Merkle–Damgård construction SHA-1/SHA-2 use. Implemented directly from the FIPS 202 specification and verified against known test vectors.
Keccak-256 is the original Keccak submission, before NIST changed one padding byte when it standardised SHA-3, so the two give completely different results for the same input. Ethereum and Solidity's keccak256() use the original, which is why it's offered separately here. If a "SHA3-256" hash from a blockchain tool doesn't match, try Keccak-256.