Compute a file checksum (hash): SHA-256, SHA-1, SHA-384/512, MD5 or CRC-32. All local in your browser, the file never leaves your device.
Running locally on your device ...
Running locally on your device ...
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Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
A checksum is a short fingerprint of a file: from any number of bytes a hash function computes one fixed, short value. Change even a single bit of the file and the checksum comes out completely different. That is exactly why many providers publish the SHA-256 value next to a download: you compute the checksum of your downloaded file yourself and compare it with the published value. If both match, the file arrived complete and unchanged.
This tool computes the common methods. SHA-1/256/384/512 (FIPS 180-4) run via the native Web Crypto interface; SHA-256 is today’s standard and the right choice when nothing else is required. SHA-1 is considered outdated and should no longer be used for security checks, but it is still useful for matching older systems. SHA-384 and SHA-512 give longer values from the same family. MD5 (RFC 1321) is even older and cryptographically broken (collisions can be crafted deliberately), but many older downloads and tools still publish it as the reference value. CRC-32 is not a cryptographic checksum but a fast integrity check in the ISO-HDLC variant (polynomial 0xEDB88320), the kind built into ZIP archives and PNG files: good for spotting random transfer errors, not for ruling out tampering.
The computation runs entirely locally in your browser, via the native Web Crypto interface (for SHA) and a tiny pure-JavaScript routine (for CRC-32). Nothing is uploaded, nothing is stored, and no foreign library is loaded from a CDN. The result appears as a text file in the same format as the command-line tools sha256sum or certutil, so you can compare it directly with a value produced elsewhere.
| Output format | TXT |
|---|---|
| Batch processing | Yes |
| Processing | Locally in your browser (JavaScript) |
| File upload | None |
Limitations: A checksum proves that two files are byte-for-byte identical; it does not encrypt anything and does not protect against eavesdropping. MD5, SHA-1 and CRC-32 are unsuitable for security purposes (CRC-32 only catches random errors; MD5 and SHA-1 can be deliberately collided) - against deliberate tampering use SHA-256 or larger. The reference value must come from a trustworthy source.
| Algorithm | Output length | Status | Typical use |
|---|---|---|---|
| SHA-256 | 256 bits | Today's standard | Downloads, general verification |
| SHA-1 | 160 bits | Outdated (not for security) | Matching older systems |
| SHA-384 | 384 bits | Longer SHA-2 variant | Where a longer checksum is required |
| SHA-512 | 512 bits | Longer SHA-2 variant | Where a longer checksum is required |
| MD5 | 128 bits | Cryptographically broken | Reference value for older downloads/tools |
| CRC-32 | 32 bits | Not a cryptographic checksum | Detecting random transfer errors (ZIP, PNG) |
No. The checksum is computed entirely locally in your browser; the file never leaves your device and is not stored.
When in doubt, SHA-256 - it is today’s standard. Use MD5, SHA-1 or CRC-32 only when a system explicitly expects that value.
Compute it here and compare the value character by character with the published one. If they match, the file is unchanged.
CRC-32 is a fast check against random transfer errors (as in ZIP and PNG), but it is not cryptographically secure. SHA-256 also detects deliberate tampering.
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