Application Security
Password Entropy Calculator
Enter a password to compute entropy in bits, charset size, and estimated crack time against bcrypt, Argon2id, MD5, and plain text storage. Computed locally — not transmitted.
No data is transmitted — everything runs locallyTool
Example — A 28-character mixed-set passphrase used as a strong production credential example.
Entropy
183.5 bits
log₂(charsetˡᵉⁿᵍᵗʰ)
Strength
Very Strong
NIST SP 800-63B scale
Charset Size
94 chars
unique characters used
Crack Time
5.61396042763968e+34B years
at 10B guesses/sec (GPU)
About this tool
Password Entropy Calculator
The Password Entropy Calculator computes entropy bits from character set and length, estimating offline crack time against bcrypt, Argon2id, and weaker hash functions.
• Check whether a password meets NIST SP 800-63B entropy recommendations
• Compare diceware passphrase entropy against a typical 12-character password
• Explain crack time differences between bcrypt and MD5 to a development team
• Calculate entropy for a randomly generated API key or token
Affiliate disclosure
Credential and secrets management for teams. 1Password provides enterprise password management and secrets infrastructure for development teams.
View passwords with 1Password
External site · Independent provider · We may receive a commission · Not a recommendation
FAQ
What does this tool tell you?
The Password Entropy Calculator computes entropy bits from character set and length, estimating offline crack time against bcrypt, Argon2id, and weaker hash functions.
What affects the result most?
Entropy = length × log2(charset_size) — bits of randomness in a password. Charset sizes: lowercase=26, lowercase+upper=52, +digits=62, +symbols=95, full ASCII=128. Crack time at 10B guesses/sec: 2^entropy / 10^10 seconds — modern GPU hashcat benchmark.
How should I use the result?
The calculation is deterministic — the same inputs always produce the same output — so the most useful workflow is to vary one input at a time and see which factor moves the result most. That tells you where to focus your attention before committing to a decision.