Password Strength Checker
Estimate password entropy and strength level from length and character variety.
Input Data
Password
Results
Estimated entropy in bits.
66
Assigned strength level.
強
Explanatory note about the result.
長度 10、字符集 95 → 熵 66 bits（強）。
At a glance:Charset: lowercase 26, uppercase 26, digits 10, symbols ~33 (95 total). Entropy = length × log2(charset size); levels: <40 weak, 40–64 medium, 64–128 strong, >128 very strong. Complements password-generator.
Formula
Charset size R = sum of character classes hit (lower/upper/digit/symbol).
Entropy = length × log2(R).
How to Use
- Type a password.
- The tool returns entropy and a strength level.
Case Studies
Abc123!xyz (9)
R = 95; entropy ≈ 9 × 6.57 ≈ 59 bits → medium.
FAQ
Is a higher entropy always safer?
Yes for random passwords; entropy estimates guessing difficulty, not dictionary weakness.
Related Tools
References
Content review: Calculatorism Safety Team. Results are for reference only; please refer to the relevant authorities for the official figures.