Checksum

When you download something important – an installer, a backup, a document – its publisher often lists a checksum: a unique fingerprint. If your file's fingerprint matches the one they published, it's almost certainly the same file they released – it arrived intact; if it doesn't match, it was corrupted or altered along the way. (A checksum is only as trustworthy as the fingerprint you check against, so use one from a source you trust.) Drop your file below to check – the fingerprint is computed entirely in your browser; your file is never uploaded anywhere.

Drop a file here, or click to choose

It stays on your device.

MD5 is for compatibility, not security. Many publishers still list an MD5, and it's fine for matching what they posted – but it can be deliberately forged, so it can't prove a file wasn't tampered with. For tamper-proofing, prefer SHA-256.

Fingerprint

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Your browser can't hash locally here. Open this page over https (or localhost) – secure context is required.

Computed in your browser using its built-in cryptography. Your file never leaves this device.