Privacy First
Your password is NOT sent anywhere. All analysis happens 100% locally in your browser using the zxcvbn library.
Check Your Password
Need a strong password?
Generate secure passwords with our generator
Strength Levels
What Makes a Strong Password
- At least 12-16 characters long
- Mix of uppercase, lowercase, numbers, and symbols
- No dictionary words or common phrases
- No personal information (names, birthdays)
- Unique for each account
How It Works
This tool uses zxcvbn, an open-source password strength estimator developed by Dropbox.
Unlike simple rules-based checkers, zxcvbn recognizes common patterns like keyboard patterns, repeated characters, sequences, common words, names, and dates to provide realistic strength estimates.
Understanding Password Strength
Password strength is measured by how resistant it is to guessing attacks. This tool uses zxcvbn, an open-source library developed by Dropbox, which realistically estimates how long it would take to crack your password.
Unlike simple rule-based checkers, zxcvbn recognizes common patterns like keyboard sequences (qwerty), repeated characters (aaa), l33t speak (p@ssw0rd), and dictionary words, providing accurate strength assessments.
Frequently Asked Questions
Is it safe to check my password here?
Yes. Your password never leaves your browser. All analysis is performed locally using JavaScript. No data is sent to any server. You can verify this by checking your browser's network tab or using the tool offline.
What is password entropy?
Entropy measures the randomness of a password in bits. Higher entropy means more possible combinations an attacker must try. A password with 80 bits of entropy would require 2^80 guesses to crack by brute force.
Why is my complex password rated weak?
Passwords like "P@ssw0rd123!" look complex but use predictable patterns. Attackers know these substitutions (@ for a, 0 for o) and try them first. True strength comes from length and randomness, not predictable complexity.
What crack time should I aim for?
For important accounts, aim for "centuries" or more against offline attacks. Online attacks are slower due to rate limiting, but offline attacks against stolen password hashes can try billions of combinations per second.