Password design — verify a password has enough entropy.Token review — confirm random tokens are unguessable.Education — visualize how charset and length combine.Compliance — meet entropy minimums for security policies.

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Entropy Calculator

Calculate password or string entropy in bits. Charset detection, length analysis, crack time estimate. Runs 100% in your browser.

Password or string

Reference

What is entropy?

Entropy measures unpredictability in bits. A password with N characters from a charset of size C has log2(C^N) bits of entropy. 40 bits is weak; 60 bits is moderate; 80+ bits resists offline brute force on modern hardware. Crack time estimates assume 10 billion guesses per second.

Common uses

Password design — verify a password has enough entropy.
Token review — confirm random tokens are unguessable.
Education — visualize how charset and length combine.
Compliance — meet entropy minimums for security policies.

Privacy

All calculations run 100% in your browser. No data is sent to any server.

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