Password Strength Checker — Analyze Password Security Online
Free online password strength checker with real-time entropy calculation, pattern detection, crack-time estimates, and actionable security suggestions. Test and analyze your password security instantly — 100% client-side, nothing leaves your browser.
100% client-side. Your password never leaves this browser tab — analysis is performed locally in JavaScript.
Type a password above to analyze its strength
Analysis happens instantly, locally, and privately
How to Use
Enter a Password
Type or paste any password in the input field. Analysis starts immediately.
Review Strength Score
Check the overall rating from Very Weak to Very Strong, plus entropy bits and crack times.
Check Requirements
See which character-type requirements are met and which are missing. View detected patterns.
Improve Your Password
Follow the suggestions panel — add length, mix character types, or use a passphrase.
Frequently Asked Questions
Entropy = length × log₂(charset size). For example, a 12‑char password with mixed case, digits, and symbols yields about 72 bits of entropy.
They estimate how long an attacker with the hash would take via brute force. Offline GPU attacks can try 100+ billion guesses per second.
Length matters most (12+ characters). Combine uppercase, lowercase, digits, and symbols. Avoid dictionary words, keyboard patterns, and repeats.
No. Everything runs locally in JavaScript — your password never leaves this browser tab.
Entropy measures unpredictability in bits. A password with 50 bits of entropy is 2⁵⁰ times harder to guess than one with 30 bits.
Crack times assume the attacker has the password hash. Online attacks are slower due to server throttling; offline GPU attacks can try billions of guesses per second.
Examples
Example Password Check
P@ssw0rd123
11 chars | 69 charset | 67 bits entropy
Fair — crack time: ~3 hours (GPU)
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