Hash & Checksum Calculator (MD5, SHA-1, SHA-256, SHA-512)
Compute the hash or checksum of a text (MD5, SHA-1, SHA-256 or SHA-512) directly in your browser — nothing uploaded to any server.
Which algorithm to choose
SHA-256 is the most widely used today for integrity checks and Git commit fingerprints. MD5 and SHA-1 are still very common as a file checksum (many downloads publish their MD5 or SHA-1), but neither is cryptographically secure anymore: both have known collisions and shouldn't be used for passwords, signatures, or anything that depends on it being impossible to craft two inputs with the same hash. SHA-512 produces a longer fingerprint (128 characters) than SHA-256, with the same practical security level.
What it's used for
The most common use is verifying that a file or message hasn't been altered: you compute the hash before and after (for example, after downloading a file) and, if they match, the content didn't change by even a single byte. It's also used for Git commit fingerprints, certificates, digital signatures, or as part of authentication systems. No hash is reversible: there's no way to recover the original text from the result.
How it's computed here
SHA-1, SHA-256 and SHA-512 are computed with crypto.subtle.digest, the browser's native crypto API (Web Crypto). MD5 isn't available in that API in any browser, so it's computed with a plain JavaScript implementation, verified against the algorithm's official test vectors (RFC 1321).
To encode the result itself as Base64 instead of hex, or to work with Base64 of other text, use Base64 encode/decode.