How long is a MD5 hash?

A MD5 digest is 128-bit, written as 32 hexadecimal characters. 32 hexadecimal characters (0-9, a-f). Note that NTLM hashes are also 32 hex characters, so length alone cannot tell them apart — this tool tries both.

MD5 Decrypt & Reverse Lookup

Q: Can MD5 be decrypted?

No. MD5 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 MD5 safe for storing passwords?

No. MD5 is fast, which is exactly the wrong property for a password hash. A modern GPU computes billions of MD5 digests per second, so an attacker does not need to break the maths — they simply hash every candidate password until one matches. A precomputed lookup takes that further: hash the candidates once, store them sorted, and every future lookup is a binary search. Use bcrypt, scrypt or Argon2, which are deliberately slow and salted.

MD5 produces a 32-character hexadecimal digest and is the hash most often found in older databases, forum software and legacy PHP applications. It is also the most thoroughly broken.

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What a MD5 hash looks like

plaintext	password
MD5 digest	5f4dcc3b5aa765d61d8327deb882cf99
digest size	128-bit — 32 hex characters
published	1991, by Ronald Rivest
identify it by	32 hexadecimal characters (0-9, a-f). Note that NTLM hashes are also 32 hex characters, so length alone cannot tell them apart — this tool tries both.

Can MD5 be decrypted?

Strictly, no — and any tool claiming to "decrypt" it is describing the wrong operation. MD5 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 MD5 hashes fall to lookup

MD5 is fast, which is exactly the wrong property for a password hash. A modern GPU computes billions of MD5 digests per second, so an attacker does not need to break the maths — they simply hash every candidate password until one matches. A precomputed lookup takes that further: hash the candidates once, store them sorted, and every future lookup is a binary search.

Do not use MD5 for passwords. Broken in 2004. Use bcrypt, scrypt or Argon2 instead.

History

MD5 was designed by Ronald Rivest in 1991 as a successor to MD4. In 2004 a Chinese team led by Xiaoyun Wang demonstrated practical collisions — two different inputs producing the same digest — and by 2008 researchers had used chosen-prefix collisions to forge a working CA certificate. MD5 has been unfit for any security purpose for over two decades, yet it remains extremely common in legacy systems.

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 MD5 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.

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