What is Hash function?
A hash function maps input data of any size to a fixed-size string of bytes (the hash or digest). The same input always produces the same output, small input changes produce very different outputs, and the process is one-way — you cannot reverse a hash back to its input.
Good cryptographic hashes are deterministic, one-way, and collision-resistant (it is infeasible to find two inputs with the same hash). Examples include MD5 and SHA-1 (now broken for security) and SHA-256 (the modern standard).
Hashes are used for file-integrity checks, digital signatures, deduplication and — with a salt and a slow KDF like bcrypt or argon2 — password storage.
Hash function tools
Hash Generator — All Algorithms
Compute MD4, MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA3, Keccak-256, CRC-32 and NTLM hashes of text or files in your browser.
Open toolSHA-256 Hash Generator
Compute SHA-256 digest of text or files in your browser using Web Crypto API. Output in hex or Base64.
Open toolMD5 Hash Generator
Compute MD5 digest of text or files (up to 50 MB) in your browser. Output in hex or Base64.
Open toolSHA-1 Hash Generator
Compute SHA-1 digest of text or files in your browser using Web Crypto API. Useful for Git commit hashes and legacy systems.
Open toolFrequently asked questions
Can you reverse a hash?
No — hashing is one-way. You can only verify by hashing a candidate input and comparing, or brute-force/guess for weak inputs.
Which hash function should I use?
SHA-256 for security. MD5 and SHA-1 are broken and should only be used for non-security checksums.