Low entropy password
password = abc123
Result: ~28.5 bits - can be cracked in seconds.
Password Entropy Calculator
Calculate how much entropy (randomness) a password contains. Entropy is measured in bits - each bit doubles the number of possible combinations. This tool shows the charset size, length, and total entropy, helping you understand how resistant a password is to brute-force attacks.
Privacy: this tool processes all data entirely in your browser. Passwords and hashes are never sent to the server.
Enter your values and press Calculate — the result appears here.
Worked examples
High entropy password
password = xK9!mP2$vL5@nQ8
Result: ~92 bits - would take centuries to crack.
Frequently asked questions
What is entropy?
Entropy measures the unpredictability of a password in bits. Each bit doubles the number of possible combinations. A password with 80 bits of entropy has 2^80 (about 1.2 × 10^24) possible combinations.
How much entropy do I need?
For most online accounts: 60+ bits. For high-security applications: 80+ bits. For encryption keys: 128+ bits. Password managers can handle arbitrarily long passwords, so use 20+ characters when possible.
Why does charset size matter?
Charset size is the number of unique characters your password draws from. A password using only lowercase letters (26 chars) has less entropy per character than one using all printable ASCII (95 chars). Mixing character types increases entropy exponentially.
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