Hash Identifier

Paste a hash and see which algorithms produce a string of that shape. Identification works from length and prefix, so a 32 character hex string narrows to MD5, NTLM, or MD4, while a value starting with a dollar sign and 2a is recognisable as bcrypt.

Hash String

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Why use Hash Identifier?

Every hash algorithm produces a fixed size output, and that size is the first thing to look at. Rendered as hexadecimal, each byte becomes two characters, so a 128 bit digest is 32 characters, 160 bits is 40, and 256 bits is 64. Counting the characters gets you most of the way to an answer. The limit of that approach is that bit length is not unique to an algorithm. SHA-256 and SHA3-256 are entirely different constructions that happen to output the same size, and no amount of staring at the hex will separate them. This is why the tool lists every candidate rather than picking one, and why knowing the source of the hash usually matters more than the hash itself. Password hashes are the easier case. Modern schemes use the modular crypt format, which prefixes the value with the algorithm identifier and its parameters, so bcrypt and Argon2 announce themselves. Seeing a bare MD5 or SHA-1 in a password column is itself a finding, because fast general purpose digests were never designed for storing credentials.

Key benefits

Covers raw hex digests and the prefixed crypt formats in one place
Honest about ambiguity, listing every algorithm that fits rather than guessing one
Reports the character count when nothing matches, which is the next useful clue
Recognises modern password hashing formats, not only legacy digests
Runs locally, so a hash from your own system is never transmitted

Features

Hex length matching for MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, and CRC32
Prefix matching for bcrypt, Argon2, and the MD5, SHA-256, and SHA-512 Unix crypt schemes
Case insensitive on hex input
Live identification as you type
Multiple candidate names shown where the format is genuinely ambiguous

Popular use cases

Working out what a hash column in an inherited database actually contains
Identifying a digest published alongside a download
Learning to recognise password hash formats during security training
Checking whether a legacy system is still storing passwords with a bare digest

How to use Hash Identifier

1
Paste the hash
Drop the full string in, including any prefix such as $2a$ or $argon2id$, since the prefix carries the identification.
2
Read the candidates
Matching algorithms are listed. More than one name means several algorithms share that output shape.
3
Narrow it by context
If nothing matched, the character count is shown so you can compare it against a format the tool does not cover.
4
Use the length as a clue
Hex length maps directly to bit length: 32 characters is 128 bits, 64 is 256 bits.

Frequently asked questions

Can a hash be identified with certainty?

Not from the string alone. Length and prefix narrow the field, but any two algorithms with the same output size produce indistinguishable hex. A 64 character hex string could be SHA-256 or SHA3-256, and nothing in the value itself separates them. Where the hash came from is usually the deciding clue.

Why does a 32 character hash list three possibilities?

MD5, NTLM, and MD4 all produce 128 bit output, which is 32 hex characters. NTLM is specific to Windows password storage, so context tells you which one you are looking at far better than the string does.

What do the dollar sign prefixes mean?

They are the modular crypt format, which stores the algorithm, cost parameters, and salt alongside the hash. $2a$ is bcrypt, $6$ is SHA-512 crypt, and $argon2id$ is Argon2 in its recommended variant. Because the format is self describing, these are identifiable with certainty.

Can this reverse a hash?

No, and nothing can. Hashing is one way by design. Recovering the input means guessing candidates and hashing each one until the output matches, which is what cracking tools do. This page only tells you which algorithm was likely used.

Is my hash uploaded anywhere?

No. Matching is done with pattern rules in the page, and nothing you paste is sent to a server.

Last reviewed: July 2026

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