Free Online Password Strength & Entropy Checker

Calculate password entropy, crack time estimations, and identify dictionary weaknesses.

Strength Rating None
Checklist:
❌ At least 12 characters
❌ Uppercase letters (A-Z)
❌ Lowercase letters (a-z)
❌ Numbers (0-9)
❌ Special symbols (!@#$)
Client-Side Guarantee: Processed 100% locally in your browser. No files or data are uploaded.

How to Use the Password Strength Checker

  1. Type your password into the tester.
  2. View real-time entropy score and crack time estimate.
  3. Review suggestions to improve security.

Key Features

✓ Calculates Shannon entropy in bits
✓ Estimates brute-force crack time
✓ Identifies repeated sequences and common words
✓ 100% private: password never leaves your browser

About Password Strength Checker

Analyze password robustness client-side. Calculates mathematical entropy bits, estimated crack times against supercomputers, and warns of common patterns.

Frequently Asked Questions

Is it safe to type my real password here?

Yes! The calculation runs 100% locally in JavaScript. No data is sent over the network.

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