Password Entropy Calculator
Calculate the entropy (bits of randomness) and estimated crack time of any password based on its character set and length.
Analyzed entirely in your browser — never sent to any server.
About Password Entropy Calculator
Password entropy measures unpredictability. It is calculated as length × log₂(charsetSize). A password using only lowercase letters has a charset of 26; adding uppercase doubles it to 52; adding digits and symbols expands it further. At 1 billion guesses per second (modern GPU brute force): 36 bits ≈ 1 minute; 60 bits ≈ 37 years; 128 bits ≈ heat death of the universe.
Private & free — this tool runs entirely in your browser.
Recommended: IndieKit — Ship your Next.js startup in days.affiliate
Related Cryptography & Security tools
Password Generator
Generate strong, random passwords locally.
Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes locally.
JWT Decoder
Decode JSON Web Tokens instantly and offline.
Bcrypt Generator
Generate and verify Bcrypt hashes with custom salt rounds.
MD5 Hash Generator
Generate an MD5 hash from any text.
SHA-1 Hash Generator
Generate a SHA-1 hash from any text.
SHA-256 Hash Generator
Generate a SHA-256 hash from any text.
SHA-512 Hash Generator
Generate a SHA-512 hash from any text.