How long is a SHA-256 hash?

A SHA-256 digest is 256-bit, written as 64 hexadecimal characters. 64 hexadecimal characters.

SHA-256 Decrypt & Reverse Lookup

Q: Can SHA-256 be decrypted?

No. SHA-256 is a one-way hash function and cannot be mathematically reversed. What lookup tools do is search a precomputed index of previously hashed passwords for one that produces the same digest.

Q: Is SHA-256 safe for storing passwords?

No. This is the part people find surprising: a perfectly secure hash function still makes a bad password store. SHA-256 is designed to be fast, and speed is the enemy here. If a site stores unsalted SHA-256 password hashes, every password that has ever appeared in a wordlist is recoverable by lookup — the algorithm being unbroken is irrelevant, because nothing is being broken. Use bcrypt, scrypt or Argon2, which are deliberately slow and salted.

SHA-256 produces a 64-character hexadecimal digest and is part of the SHA-2 family. Unlike MD5 and SHA-1 it has no known practical collisions and remains cryptographically sound.

▶ Open the SHA-256 lookup tool

What a SHA-256 hash looks like

plaintext	password
SHA-256 digest	5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8
digest size	256-bit — 64 hex characters
published	2001, by the NSA
identify it by	64 hexadecimal characters.

Can SHA-256 be decrypted?

Strictly, no — and any tool claiming to "decrypt" it is describing the wrong operation. SHA-256 is a one-way function: it destroys information, so there is no key and no inverse. What actually happens is a lookup. Enormous numbers of candidate passwords are hashed in advance and stored sorted by digest. Recovering a password means finding the digest in that index, not reversing anything.

The practical consequence: a password that has never appeared in any wordlist or breach will not be found here, no matter how weak it looks. A password that has appeared will be found almost instantly.

Why SHA-256 hashes fall to lookup

This is the part people find surprising: a perfectly secure hash function still makes a bad password store. SHA-256 is designed to be fast, and speed is the enemy here. If a site stores unsalted SHA-256 password hashes, every password that has ever appeared in a wordlist is recoverable by lookup — the algorithm being unbroken is irrelevant, because nothing is being broken.

Still cryptographically sound. SHA-256 has no known practical break. The weakness below is about how it is used for passwords, not about the algorithm itself.

History

SHA-256 was published by the NSA in 2001 as part of SHA-2. It has withstood twenty-five years of analysis with no practical break, and it underpins TLS certificates, Bitcoin's proof of work, and file integrity verification across the industry. There is no reason to stop using SHA-256 for the jobs it is designed for.

What to use instead

If you are storing passwords, use bcrypt, scrypt or Argon2id. All three are deliberately slow and salted: the salt makes every stored hash unique, so a precomputed index cannot exist, and the cost factor means an attacker gets thousands of guesses per second instead of billions. That is why this tool is useless against them — by design, and that is the point.

Look up a SHA-256 hash

The lookup runs against a corpus of over a billion real passwords, covering MD5, SHA-1, SHA-256 and NTLM. It is free, needs no account, and no hashes are retained.

▶ Open the lookup tool