Password Strength
Check the strength and security of a password.
About Password Strength
Password Strength Checker evaluates your password against criteria including length, character variety, common patterns, and dictionary words, then gives an overall strength rating and specific suggestions for improvement. It uses the zxcvbn algorithm, which models realistic attacker behavior rather than just counting special characters. No password is ever sent to a server — everything runs in your browser.
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Frequently Asked Questions
Is Password Strength free?
Yes, completely free. No signup, no account, no usage limits. Use it as much as you need.
Is my data secure?
All processing happens directly in your browser using JavaScript. Your data is never sent to any server, stored, or shared. It stays entirely on your device.
Does the tool send my password anywhere?
No. Strength checking runs entirely in your browser using the zxcvbn library. Your password never leaves your device.
What makes a password "strong" according to this tool?
Length and unpredictability matter most. Passwords that are long (16+ characters), avoid dictionary words and common substitutions (p@ssw0rd), and use a mix of character types score highest.