Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text, instantly and entirely in your browser. Nothing you type is ever sent to a server.
A hash turns any input into a fixed-length string of characters. The same input always gives the same hash, and even a tiny change to the input produces a completely different one, which is what makes hashes useful for checking that a file or a piece of text has not been altered.
This tool computes the common hashes in your browser as you type. Nothing you enter leaves your device.
For anything security-related, use SHA-256 or stronger. SHA-256 is the modern default and is what most systems expect.
MD5 and SHA-1 are included because people still need them for legacy checksums, but both are broken for security use: it is possible to construct two different inputs with the same MD5 or SHA-1 hash. Never use them to verify anything an attacker might tamper with. For a simple "did this file download correctly" check where nobody is trying to cheat, they are still fine.
A hash is one-way. You cannot turn a hash back into the original input, which is exactly why passwords are stored as hashes rather than as text. Encryption is two-way and needs a key. If you need to get the data back, you want encryption, not a hash.
No. All hashing happens in your browser using the built-in Web Crypto API and a local MD5 implementation. Nothing is uploaded.
Because plenty of older systems still use them for non-security checksums, and people need to match those. Just do not rely on them where security matters.
No. Hashing is one-way by design. So-called "hash reversers" are really just lookup tables of previously seen inputs; they cannot reverse an arbitrary hash.
That is the defining property of a hash function, and it is what lets you use a hash to verify that data has not changed.