Password Strength Checker

Your password never leaves your browser. All analysis is done locally.
Enter Password

About this tool

Check how strong your password is with entropy analysis, crack time estimation at different attack speeds, composition breakdown, and common password detection. Your password is never sent anywhere — all analysis happens in your browser.

How password strength is measured

Password strength is primarily determined by entropy — the number of bits of randomness. Higher entropy means more possible combinations an attacker must try. Entropy depends on password length and the character set used (lowercase, uppercase, digits, special characters).

  • Entropy calculation in bits
  • Crack time for different attack speeds
  • Common password detection (top 100)
  • Repeated and sequential character checks
  • Character composition breakdown
  • Strong password generator
  • Privacy-first: nothing leaves your browser

100% free. No signup. No data collected anywhere.