Keccak-256
Hash text or hex the way Ethereum and Solidity do — not SHA3.
Runs offline
Input encoding
Paste text or hex. A function signature also yields its 4-byte selector.
About keccak-256
Keccak-256 is the hash function Ethereum uses everywhere: storage slots, event topics, contract addresses, and the four-byte selector at the front of every function call. It is not the same as SHA3-256 — the padding differs, so a generic SHA3 tool will give you the wrong answer for anything Ethereum-related. Paste a function signature and the four-byte selector is calculated for you as well.
Common questions
Is Keccak-256 the same as SHA-3?
No. Ethereum Keccak-256 is the pre-standardisation SHA-3 candidate; NIST SHA-3 uses different padding. Hashing the same input with a SHA-3 library usually yields a different digest, which is why Solidity keccak256 and this page use the Ethereum variant.
What is a function selector?
The first four bytes of the Keccak-256 hash of a function signature such as transfer(address,uint256). Wallets and explorers use that prefix to name a call; colliding names that share those four bytes are why a selector lookup sits beside the hasher.
Does hashing here send my data anywhere?
No. The hash is computed in this browser with the same algorithm the EVM uses. Nothing you paste is uploaded, logged, or retained by a server of ours — the tab does the work and is the only place the input exists.