SHA3-256 Hash Generator
Generate the SHA3-256 hash of any text instantly in your browser. UTF-8, hex or Base64 input; hex or Base64 output. Free, private, no upload.
Runs entirely in your browser. Your data is never uploaded.
What is SHA3-256 Hash Generator?
SHA3-256 is the 256-bit fixed-length hash from the SHA-3 standard (FIPS 202, 2015), based on the Keccak sponge rather than the SHA-2 design. This tool computes the 256-bit SHA3-256 digest of text or raw bytes (hex or Base64) as you type and shows it as 64 hex characters or Base64.
How to use SHA3-256 Hash Generator
- Type or paste your input into Text to hash — the digest updates as you type (an empty box shows the hash of empty input).
- Choose the Input encoding: Text (UTF-8) hashes the characters as UTF-8, Hex bytes or Base64 hash the decoded raw bytes.
- Pick the Output format (hex lowercase, hex uppercase or Base64) and click Copy.
Example
abc
3a985da74fe225b2045c172d6bd390bd855f086e3e9d525b46bfe24511431532
SHA3-256 of the 3 ASCII bytes "abc" (UTF-8, hex lowercase output), the standard test vector.
When to use SHA3-256 Hash Generator
Use the SHA3-256 text tool to hash strings: reproduce a value from documentation or code, build test vectors, compare an API signature input, or check what a program should output. Do not use it to check a downloaded file: copying file contents into a text box changes line endings and encoding, so use the SHA3-256 file checksum tool. If you are working with Ethereum or other software that says "SHA3" but predates FIPS 202, you probably need Keccak-256 instead.
How SHA3-256 Hash Generator works
SHA3-256 is a sponge over the 1600-bit Keccak-f permutation (24 rounds of θ, ρ, π, χ and ι). The input is absorbed in 1088-bit blocks (the rate; capacity 512 bits), padded with the SHA-3 domain suffix 01 followed by pad10*1 (byte 0x06 … 0x80). After absorbing, the first 256 bits of the state are squeezed out as the digest. The suffix is the only difference from the original Keccak-256, but it changes every output. The text is first converted to bytes (UTF-8 by default), so the same characters always give the same hash.
Common Use Cases
- Check the expected SHA3-256 of a string in a unit test or fixture
- Hash hex bytes copied from a debugger, packet capture or protocol spec
- Compare SHA3-256 output between two programming languages that disagree
- Generate deterministic identifiers or cache keys from text
- Get the Base64 form of a SHA3-256 digest for headers or configuration files
Security Note
SHA3-256 has no known practical attacks. Plain hashes are also not suitable for storing passwords: use a slow, salted password hash such as Argon2, scrypt or bcrypt. Everything is computed locally in your browser; nothing you type is sent anywhere.
FAQs
Why does my SHA3-256 not match Ethereum or an older library?
Ethereum and some older libraries use the original Keccak submission, which pads with 0x01 instead of the FIPS 202 suffix 0x06. The outputs are completely different; use the Keccak-256 tool for those values.
Is SHA3-256 better than SHA-256?
Both are secure. SHA-3 is a different construction (a sponge), so it offers diversity if SHA-2 were ever weakened, and it is immune to length extension. SHA-2 is faster in software and more widely deployed.
Why does the hash change completely when I change one character?
That is the avalanche effect every cryptographic hash is designed for: flipping one input bit changes about half of the 256 output bits, so similar inputs give unrelated digests.
Does a trailing space or newline matter?
Yes. The hash covers every byte, so abc and abc followed by a newline give different SHA3-256 values. Make sure the input contains exactly the bytes you intend to hash.