Online Password Entropy Calculator
Detects the character pool in real time (lowercase 26 / uppercase 26 / digits 10 / symbols 33 / other unicode chars counted individually), computes entropy = length × log2(pool), shows combinations in scientific notation and a five-level strength rating, fully local.
How to Use
- Type or paste the password to evaluate
- See entropy and estimated crack time live
- Strengthen the password based on suggestions
- All encoding/decoding runs locally; sensitive content never leaves your device
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FAQ
How is password entropy computed?
The pool size N is determined by which character classes appear (lowercase 26, uppercase 26, digits 10, common symbols 33, plus each distinct other unicode character). Entropy = length × log2(N), measured in bits.
How are strength ratings defined?
Five levels by entropy: <28 weak, 28-35 fair, 36-59 strong, 60-127 very strong, ≥128 extremely strong. Ratings reflect brute-force difficulty only, not how a site stores passwords.
Is my password uploaded?
Never. All calculations run locally in your browser in real time, the input is masked by default, and nothing is recorded or sent to any server.