What is a file hash and why verify it?
A hash (checksum) is a short fingerprint computed from a file's entire contents. Change even one byte of the file and the fingerprint changes completely. That makes hashes the standard way to answer two everyday questions: "Is this download exactly what the developer published?" and "Are these two files identical?"
Software projects publish a SHA-256 checksum next to their download links precisely for this. After downloading, you compute the hash of your copy and compare. A match proves the file wasn't corrupted in transit and wasn't tampered with by a mirror, proxy, or malware. A mismatch means: don't run that installer.
This tool computes three common algorithms at once: SHA-256 (the modern standard you should prefer), SHA-1 and MD5 (older, still widely published for legacy reasons — fine for integrity checks, no longer trusted against deliberate forgery). Paste the expected hash into the field above and the tool highlights the match automatically — no squinting at 64 hex characters.
Files you verify are often installers, backups or private archives. Hashing here happens fully on your device via the browser's built-in crypto engine — nothing is uploaded, and there are no artificial size limits.