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Password Strength Checker

Real-time scoring, crack-time estimates, and a secure password generator.100% client-side. Your password never leaves your browser.

Security Criteria
✗At least 8 characters
✗Contains lowercase letters
✗Contains uppercase letters
✗Contains numbers
✗Contains special characters (!@#$%^&*)
✗12+ characters recommended
✗16+ characters for best security
✗Not a common password
✗No sequential patterns (abc, 123)
✗No repeating characters (aaa, 111)
Password Generator
Click Generate
16
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Security Tips
1Never reuse passwords across different sites or services
2Use a password manager to generate and store unique passwords
3Enable two-factor authentication (2FA) wherever possible
4Avoid personal info like birthdays, pet names, or addresses
5Consider using passphrases: random words like "correct-horse-battery-staple"
6Change passwords immediately if a service reports a data breach
Need a password manager?

A password manager generates, stores, and auto-fills unique passwords for every site. See how the top options compare.

1Password vs Bitwarden →LastPass vs 1PasswordDashlane vs 1Password

Frequently Asked Questions

How is password strength calculated?+

The score combines character diversity (lowercase, uppercase, numbers, symbols), length, mix bonus for using 3+ character types, and penalties for patterns like repeated characters, sequential sequences, and common passwords. Scores range from 0 (very weak) to 100 (very strong).

How is crack time estimated?+

Crack time assumes a brute-force attack at 10 billion guesses per second (a reasonable estimate for modern GPU clusters). The formula is: (character set size ^ password length) / 10,000,000,000. This gives a worst-case estimate for pure brute force -- real attacks may use smarter strategies.

Is my password sent to a server?+

No. All analysis happens 100% in your browser using JavaScript. Your password never leaves your device. Verify this in your browser's network tab -- zero requests are made with your password data.

What makes a strong password?+

Use 16+ characters with a mix of uppercase, lowercase, numbers, and symbols. Avoid dictionary words and personal info. Most importantly, use a unique password for every account and store them in a password manager.