How long is a NTLM hash?

A NTLM digest is 128-bit, written as 32 hexadecimal characters. 32 hexadecimal characters — the same length as MD5. This tool tries both when the algorithm is set to auto-detect.

NTLM Decrypt & Reverse Lookup

Q: Can NTLM be decrypted?

No. NTLM 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 NTLM safe for storing passwords?

No. Because there is nothing to slow an attacker down. A salt would make every user's hash unique and defeat a lookup table entirely; NTLM has none. Iterations would raise the cost per guess; NTLM has one. The result is that a recovered NTLM hash of any password that has appeared in a breach is effectively already plaintext. Use bcrypt, scrypt or Argon2, which are deliberately slow and salted.

NTLM is the hash Windows stores for local and domain accounts. It is what comes out of a SAM dump, an ntds.dit extraction or a responder capture, and it is the single most valuable hash type in an Active Directory assessment.

▶ Open the NTLM lookup tool

What a NTLM hash looks like

plaintext	password
NTLM digest	8846f7eaee8fb117ad06bdd830b7586c
digest size	128-bit — 32 hex characters
published	1993, by Microsoft
identify it by	32 hexadecimal characters — the same length as MD5. This tool tries both when the algorithm is set to auto-detect.

Can NTLM be decrypted?

Strictly, no — and any tool claiming to "decrypt" it is describing the wrong operation. NTLM 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 NTLM hashes fall to lookup

Because there is nothing to slow an attacker down. A salt would make every user's hash unique and defeat a lookup table entirely; NTLM has none. Iterations would raise the cost per guess; NTLM has one. The result is that a recovered NTLM hash of any password that has appeared in a breach is effectively already plaintext.

Do not use NTLM for passwords. Unsalted and uniterated by design. Use bcrypt, scrypt or Argon2 instead.

History

NTLM replaced LM in Windows NT in 1993. It is simply MD4 applied to the UTF-16 little-endian encoding of the password — no salt, no iterations, no key stretching of any kind. Two users with the same password have identical NTLM hashes on every Windows machine on earth, which is what makes pass-the-hash possible and what makes precomputed lookups so effective against it.

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 NTLM 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