Hash Identifier — Detect Hash Algorithm
Paste a hash digest and this tool analyses its length and character set to tell you which hashing algorithm almost certainly produced it — MD5, SHA-1, SHA-256, bcrypt and more.
Input length
Character set
Candidate algorithm(s)
How does this calculator work?
Hashing algorithms produce fixed-length digests, so you can identify the algorithm from the string length and character set alone. A 32-character hex string → MD5/NTLM (128 bit); 40 hex → SHA-1 (160 bit); 64 hex → SHA-256 (256 bit); 128 hex → SHA-512/Whirlpool (512 bit). Paste any hash to see all candidates.
Formula
How this is calculated
Every hashing algorithm produces a fixed-length digest. Because the output length is deterministic, you can narrow down the algorithm purely by counting characters. For example, a 32-character hexadecimal string can only be MD5, MD4, NTLM or LM Hash — all produce 128-bit (32-hex-char) digests. A 64-character hex string maps to SHA-256, SHA3-256 or BLAKE2s-256 (all 256-bit, 64 hex chars). The character set provides an additional filter: bcrypt outputs always start with "$2a
quot;, "$2bquot; or "$2yquot; and are exactly 60 characters; MySQL 5.x hashes start with an asterisk; SHA-2 family hashes encoded in base64 are recognisable from their length and padding.The identifier checks the digest against a table of well-known algorithms and their output sizes, then lists every algorithm whose digest format matches. When multiple algorithms share the same output size (e.g. MD5 and NTLM are both 32 hex characters), all candidates are shown — you need additional context (the application that generated the hash) to distinguish them.
This is pattern detection, not decryption. The tool never reverses a hash — that would require a rainbow table or brute force. It only tells you what algorithm was used, which is useful for forensics, penetration testing, or verifying hash formats before storing them.
Frequently asked questions
No. Cryptographic hash functions are one-way: identifying the algorithm tells you how it was made but not what the original input was. To look up a known plaintext you need a rainbow table or brute-force tool such as Hashcat.
MD5 and NTLM both produce 128-bit (32-hex-character) digests, so the format is indistinguishable. You must rely on context — the application or system the hash came from — to confirm which algorithm was used.
Bits is the internal width of the hash output. A 256-bit hash produces 32 bytes of output, written as 64 hexadecimal characters or 44 base64 characters. Wider outputs are harder to find collisions for.
Also known as
TG we-Calculate Editorial Team. (2026). Hash Identifier — Detect Hash Algorithm [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/hash-identifier-calculator
TG we-Calculate Editorial Team. "Hash Identifier — Detect Hash Algorithm." TG we-Calculate. 2026. https://we-calculate.com/calculator/hash-identifier-calculator.
TG we-Calculate Editorial Team, "Hash Identifier — Detect Hash Algorithm," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/hash-identifier-calculator
@misc{wecalculate_hash_identifier_calculator, title = {Hash Identifier — Detect Hash Algorithm}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/hash-identifier-calculator}}, year = {2026}, note = {TG we-Calculate} }
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