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SHA-3 hash calculator

SHA3-224, SHA3-256, SHA3-384, SHA3-512, SHAKE128, SHAKE256 and Ethereum Keccak-256, all at once. Text, hex or files, hashed locally in your browser.

Check: SHA3-256("hello world") = 644bcc7e564373040999aac89e7622f3ca71fba1d972fd94a31c3bfbf24e3938. More in the test vectors.

Own sha3.si

A short, exact-match domain for one of the world's core cryptographic standards. Ideal for a security, cryptography, blockchain or developer-tools brand.

Buy now or make an offer Why this name
New: is your website quantum-safe? Check in seconds whether a site accepts post-quantum key exchange (ML-KEM), the NIST standard built on SHA-3. →

Dedicated calculators

SHA3-256The most used SHA-3 size, 256-bit digest. SHA3-512Largest fixed digest, widest security margin. Keccak-256Ethereum and Solidity keccak256, function selectors. SHAKE256Extendable output: any length you need.

Learn SHA-3

What is SHA-3?Keccak, the sponge construction and FIPS 202, explained. SHA-3 vs SHA-256Design, security, speed and when to use which. SHA-3 vs Keccak-256Why Ethereum hashes differ from NIST SHA-3. Code examplesPython, JavaScript, Go, Rust, Java, PHP, C#, OpenSSL.

Frequently asked

Is my input sent to a server?

No. Every hash on sha3.si is computed in your browser with JavaScript. Text and files never leave your device.

What is the SHA3-256 hash of an empty string?

SHA3-256('') = a7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a

Why does my Ethereum keccak256 not match SHA3-256?

Ethereum uses the original Keccak padding, which differs from the final NIST SHA-3 standard (FIPS 202). Same permutation, different padding byte, completely different output. Use the Keccak-256 row for Ethereum.

What is SHAKE?

SHAKE128 and SHAKE256 are the extendable-output functions (XOFs) of the SHA-3 family: you choose the output length.