SHA-256 is a member of the SHA-2 family standardised by NIST in FIPS 180-4. It maps any input to a fixed 256-bit (32-byte) digest, shown here as 64 hexadecimal characters.

Is my text sent to a server?

No. The hash is computed entirely in your browser using the Web Crypto API. The text never leaves your device, so it is safe for sensitive values.

Is SHA-256 reversible?

No. SHA-256 is a one-way function. You cannot recover the original input from the digest, though identical inputs always produce identical hashes.

Why does an empty input still produce a hash?

SHA-256 is defined for the empty string and returns the fixed digest e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855.

SHA-256 Hash Generator

What this SHA-256 generator does

This tool computes the SHA-256 cryptographic hash of whatever text you enter. SHA-256 produces a fixed 256-bit output regardless of input length, displayed as 64 hexadecimal characters. It is widely used for file integrity checks, digital signatures, blockchain addresses, and password storage (with a salt and a slow KDF on top).

How it works

SHA-256 is part of the SHA-2 family defined in NIST FIPS 180-4. Your text is first encoded to bytes as UTF-8, then padded so its length is congruent to 448 modulo 512 bits, with the original bit-length appended. The message is processed in 512-bit blocks through 64 rounds of compression using eight 32-bit working variables and a set of constants derived from the cube roots of the first 64 primes. This tool delegates that work to the browser’s native crypto.subtle.digest("SHA-256", data), so it is fast and matches the standard exactly.

Tips and notes

The same input always yields the same digest — that determinism is what makes hashes useful as fingerprints.
A single changed character produces a completely different hash (the avalanche effect).
For password hashing, never use raw SHA-256; use a salted, slow algorithm such as bcrypt, scrypt, or Argon2.
Example: the text abc hashes to ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad.