Password Strength Checker
Check how strong your password is. Your password never leaves your browser — all analysis happens locally on your device.
100% Private & Client-Side
Your password is never sent to any server. All strength analysis, entropy calculation, and crack time estimation happens entirely in your browser. You can disconnect from the internet and this tool will still work.
Frequently Asked Questions
How strong is my password?
Our tool checks your password against multiple criteria: length, character variety (uppercase, lowercase, numbers, special characters), common password lists, keyboard patterns, and sequential/repeating characters. It calculates entropy and estimates how long it would take to crack using a modern GPU cluster.
Is my password sent to a server?
No. All analysis is performed entirely in your browser using JavaScript. Your password never leaves your device, is never transmitted over the network, and is never stored anywhere. You can verify this by disconnecting from the internet and using the tool offline.
What is password entropy?
Entropy measures the randomness of a password in bits. Higher entropy means the password is harder to guess. A password with 40 bits of entropy has 2^40 (about 1 trillion) possible combinations. Experts recommend at least 60 bits for important accounts and 80+ bits for critical security.
How is crack time estimated?
Crack time is estimated assuming an attacker using a modern GPU cluster capable of 10 billion guesses per second. The calculation uses the password's entropy to determine the total number of possible combinations, then divides by the guess rate. The displayed time represents the average case (half of all possibilities).