Everything is calculated locally in your browser — nothing is ever sent anywhere.
This check runs entirely in your browser using JavaScript — your password is never transmitted, stored, or sent to any server. Entropy is an estimate of how hard the password would be to guess by brute force.
By evaluating length, character variety, and common patterns or known weak passwords.
Predictable patterns based on common words are easier to crack than they appear.
A well-built checker analyzes it locally in your browser, but always be cautious with real passwords online.