A Password Strength Checker With Entropy Math and Crack-Time Estimates Strength = length × log₂(charset size) − penalties for common patterns. Crack time = 2^entropy / guesses_per_second. It's not zxcvbn, but it gets the basics right and shows users why their password is weak (bullet list of issues) instead of just a red bar with no explanation. Most password strength meters are vibes-based: a