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Password Strength Checker

Analyze password strength with a visual meter, criteria checks, and crack time estimate.

Strength —
Estimated crack time —

Criteria Checklist

☐ At least 8 characters
☐ At least 12 characters
☐ Uppercase letters (A-Z)
☐ Lowercase letters (a-z)
☐ Numbers (0-9)
☐ Special characters (!@#$...)
☐ No common patterns (123, abc, password, qwerty)

About Password Strength Checker

  • Evaluates 7 security criteria including length, character variety, and absence of common patterns.
  • Strength meter shows Weak / Fair / Strong / Very Strong based on a weighted criteria score.
  • Crack time is estimated from entropy (character set size × length) assuming 10 billion guesses per second.
  • The generate button produces a random password that passes all 7 criteria using the Web Crypto API.
  • Your password never leaves your browser — all analysis is done client-side with no server requests.

What Makes a Password Strong?

Length Every additional character multiplies the search space. 16 characters is the current minimum recommendation for sensitive accounts.
Character variety Using uppercase, lowercase, numbers, and symbols expands the alphabet from 26 to 95+ characters, making brute force exponentially harder.
Randomness Avoid predictable patterns like keyboard walks (qwerty, 12345) and dictionary words. True randomness is the strongest defense.
Uniqueness Use a different password for every account. Password managers make this practical — you only need to remember one master password.

FAQ

Is my password stored or sent anywhere?

No. Password checking happens entirely in your browser using JavaScript. Your password is never transmitted to any server.

How is crack time calculated?

Crack time is estimated from entropy (log₂ of character set size × password length), assuming an attacker can make 10 billion guesses per second — a conservative estimate for modern GPU rigs.

What are common patterns?

Common patterns include sequential digits (123, 456), sequential letters (abc, xyz), keyboard walks (qwerty, asdf), and dictionary words like "password", "admin", and "login".

Should I use the generated password?

Yes, but store it in a password manager. The generator uses the Web Crypto API for cryptographically secure randomness, making the output genuinely unpredictable.

What password manager should I use?

Popular options include Bitwarden (open source, free), 1Password, and Dashlane. Avoid storing passwords in plain text files or browser autofill without a master password.

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