Password Strength Checker
Estimate password strength, entropy, and crack time locally.
Checked entirely in your browser — your password is never sent anywhere.
Character sets used: lowercase, uppercase, digits, symbols. Tip: length matters most — aim for 12+ characters.
What makes a password strong
Strength is really about entropy — how many guesses an attacker would need. Entropy grows with both the size of the character set and, more importantly, the length: each extra character multiplies the search space. This tool estimates entropy from the character classes you use and projects a crack time against a fast offline attack (~10 billion guesses per second). It is a guide, not a guarantee — a long passphrase of common words can still be weak if it is predictable.
Generate a strong one with the password generator, then store a hash with bcrypt or the hash generator.