Hash Calculator
Real-time SHA-1 / 256 / 384 / 512 digests computed locally with WebCrypto — perfect for verifying file fingerprints.
certutil -hashfile SHA256 (Windows) or shasum -a 256 (macOS / Linux).>_ USAGE GUIDE
Paste any text and get SHA-1, SHA-256, SHA-384, and SHA-512 digests all at once. Change a single character and every digest changes completely — the fingerprint property that makes hashes useful for verifying integrity. Typical jobs: checking that a downloaded installer matches its published digest, generating a comparison baseline for config or contract text, and preparing digests for legacy APIs that require signature inputs.
- Paste your text: all four digests compute in real time as you type
- Copy a digest: one click next to each result, ready for a verification script or a colleague
- Pick the algorithm deliberately: use the same algorithm on both sides of any comparison
Computation uses the browser's built-in WebCrypto API and runs entirely on your machine — text never leaves the device and never crosses the network, so passwords and key material are safe to process. For hashing whole files (installers, archives), use the companion File Hash Checker, which supports drag-and-drop for large files with zero bytes uploaded.
>_ FAQ
Q1 · How does SHA-256 differ from MD5, and is MD5 still usable?
MD5 outputs 128 bits; SHA-256 outputs 256. MD5 has known practical collision attacks — two different inputs can be crafted to produce the same digest — so it is no longer safe for security purposes. It remains acceptable for non-adversarial uses like cache keys and deduplication. For file integrity verification and any signature-adjacent work, use SHA-256 or stronger.
Q2 · Can a hash be decrypted back to the original text?
No. Hashing is a one-way function by design: it compresses arbitrary-length input into a fixed-length fingerprint, so information is discarded and there is nothing to "decrypt". So-called "MD5 decryption" websites simply look up hashes of common strings in rainbow tables — a hit reveals a weak password, not a broken algorithm. This is exactly why password storage uses salted hashes.
Q3 · How do I verify that a downloaded file was not tampered with?
Publishers usually post the SHA-256 value of an installer. Compute the digest locally — this tool for text, the File Hash Checker for files — and compare character by character with the published value. A match means the file is intact; a mismatch means it was corrupted or modified in transit, and you should not install it.
Q4 · Why does the same input always produce the same hash?
Hashes are deterministic: the same algorithm on the same input always yields the same output — that is precisely what makes a hash usable as a fingerprint. Different algorithms produce different digests for the same input, so always confirm both sides of a comparison are using the same algorithm before suspecting the data.
Q5 · Why do some published digests use uppercase letters?
Only the hexadecimal representation differs — the content is identical. This tool outputs lowercase consistently; if the other side requires uppercase, convert after copying. When comparing, normalize the case on both sides first so a cosmetic difference does not look like a mismatch.