Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes from any text instantly. Everything runs in your browser.
A hash function takes any input and produces a fixed-length output called a hash or digest. The same input always produces the same output. But even a tiny change in the input produces a completely different hash. This makes hashes useful for verifying data integrity - if the hash matches, the data has not been tampered with.
Hash functions are one-way. You cannot reverse a hash back to the original input. This makes them useful for storing passwords - instead of storing the password itself you store its hash and compare hashes when the user logs in.
SHA-256 produces a 256-bit hash represented as a 64 character hex string. SHA-512 produces a 512-bit hash represented as a 128 character hex string. SHA-512 is stronger but both are considered secure for most purposes. SHA-256 is used in Bitcoin and most TLS certificates. SHA-512 is used when extra security margin is needed.
MD5 is no longer considered cryptographically secure. Collisions - two different inputs producing the same hash - have been found. Do not use MD5 for security purposes. It is still useful for checksums and non-security data integrity checks where speed matters more than cryptographic strength.
No. Hash functions are designed to be one-way. You cannot mathematically reverse a hash to get the original input. Rainbow tables can crack weak or common passwords by pre-computing hashes but a strong unique password cannot be reversed.
Yes. Everything runs in your browser using the Web Crypto API. Your text is never sent to any server.
Use SHA-256 for most purposes. It is fast, widely supported, and considered secure. Use SHA-512 when you need extra security margin. Avoid SHA-1 and MD5 for any security-sensitive use.