Is the SHA-256 generator free?
Yes. It is completely free to use, with no signup, no account, and no paywall.
Do I need to install anything?
No. It runs in any modern browser on desktop or mobile, with nothing to download and nothing to configure.
Does it stay local?
Yes. Hashing runs entirely in your browser, so the text you hash never leaves your device.
Can I use SHA-256 to store user passwords?
No, and this is the single most consequential misuse of the algorithm. SHA-256 is designed to be fast, and speed is the attacker's friend: commodity GPUs run billions of SHA-256 operations per second, so a leaked table of unsalted SHA-256 password hashes is cracked in hours for every password that is not extremely long and random. Password storage needs a function that is deliberately slow and memory-hard and that takes a unique per-user salt. Argon2id is the current recommendation, with scrypt, bcrypt, and high-iteration PBKDF2 as accepted alternatives.
What is SHA-256 actually good for?
Integrity, not secrecy. It is the right tool for detecting whether content changed: file checksums, content-addressed storage, deduplication keys, cache keys, ETags, Merkle trees, commit identifiers, and digital signature schemes that sign a digest rather than a whole document. It is also the building block inside HMAC-SHA-256, which is how you authenticate a message with a shared key. What it is not is a way to hide anything, because the same input always yields the same digest.
Can a SHA-256 hash be decrypted or reversed?
Not in the sense people usually mean. A hash discards information, so there is no inverse function to run. What does work is guessing: if the input came from a small or predictable set, an attacker hashes candidates until one matches, and for common passwords and short strings that lookup is instantaneous because someone has already precomputed the table. So a digest of a random 256-bit key is effectively irreversible, while a digest of the word summer is not protected at all.
Is my text uploaded to compute the hash?
No. The digest is computed by your browser's own Web Crypto implementation (crypto.subtle.digest), which is native code inside the browser. Your text never leaves the page, is never sent over the network, and is not stored. This is worth knowing because people routinely paste secrets, tokens, and personal data into hash tools.
Do two different inputs ever produce the same SHA-256 hash?
They must exist, because there are infinitely many possible inputs and only 2 to the power of 256 possible outputs, so collisions are a mathematical certainty. Finding one is another matter. No SHA-256 collision has ever been produced, and the best generic attack needs roughly 2 to the power of 128 operations, which is far beyond what any computer can do. For practical purposes you can treat a matching SHA-256 digest as meaning the inputs are identical.
Why does the same text always give the same hash?
Because that determinism is the whole point. A hash function is a pure function of its input, which is what lets two different machines independently verify that they hold the same file. It is also why an unsalted hash leaks information: identical passwords produce identical digests, so a leaked database immediately shows you which users share a password. A salt breaks that link by making each hash input unique.