Password Strength Checker
Check how strong your password is.
See strength score, estimated time to crack, and get suggestions for improvement.
Your data stays in your browser. We do not store, collect, or transmit any information you enter.
Password Strength
Password strength is determined by its entropy — the number of possible combinations an attacker would need to try.
Entropy (bits) = Length × log₂(Character Pool Size)
Character pool sizes:
- Lowercase only (a–z): 26
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- Uppercase (A–Z): 52
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- Digits (0–9): 62
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- Symbols (!@#$…): 95
Strength levels:
- Weak (< 30 bits): Cracked in seconds
- Fair (30–50 bits): Cracked in hours to days
- Good (50–70 bits): Cracked in years
- Strong (70–90 bits): Cracked in centuries
- Very Strong (90+ bits): Virtually uncrackable
Tips for strong passwords:
- Use at least 12–16 characters
- Mix uppercase, lowercase, numbers, and symbols
- Avoid dictionary words and personal info
- Consider a passphrase: 4–5 random words (e.g., “correct horse battery staple”)
- Use a password manager to generate and store unique passwords
Note: This checker runs entirely in your browser — your password is never sent anywhere.