What this tool does
A hash turns any input — a word, a file, a whole sentence — into a fixed-length fingerprint. Change even one character of the original and the result changes completely, which is exactly what makes hashing useful for confirming a downloaded file hasn't been tampered with, or that two values match without comparing them character by character.
This tool computes five hash algorithms at once — MD5, SHA-1, SHA-256, SHA-384, and SHA-512 — entirely in your browser, without ever sending your text to a server.
Why multiple algorithms
Each algorithm produces a fingerprint of a different length and comes with different guarantees. SHA-256 and SHA-512 are today's recommended standards for any integrity check that matters — neither has ever been broken in practice. MD5 and SHA-1, older and faster to compute, produce shorter fingerprints, but collisions (two different inputs producing the same hash) have been demonstrated for both: they're still fine for non-critical checksums or compatibility with existing systems, never for signing or protecting anything.
Identify mode
Given an isolated hash with no indication of which algorithm produced it, the only usable clue is its length: 32 hex characters for MD5, 40 for SHA-1, 64 for SHA-256, and so on. This mode compares the length of the pasted text against those known values and suggests matching algorithms — a useful hint, never proof, since nothing stops an unusual format from sharing the same length.
A common use case: verifying a download
Plenty of software vendors publish a file's SHA-256 hash right next to the download link. By hashing the file you received and comparing it to the published value, you confirm the download wasn't corrupted or swapped out along the way — a simple check that few people think to run.