Is my password sent anywhere when I use this tool?

No. Password strength analysis happens entirely in your browser using JavaScript. Your password is never sent to any server.

What makes a password strong?

Length is the most important factor. A 20-character password is exponentially stronger than a 12-character one. After length, using a mix of uppercase, lowercase, numbers, and symbols increases the character set size and entropy.

What is password entropy?

Entropy measures the unpredictability of a password in bits. Higher entropy means more possible combinations and a harder password to crack. 60+ bits is recommended; 80+ bits is strong for most purposes.

Password Strength Checker

Entropy score, crack time estimate, and specific tips. Your password never leaves your browser.

How Password Strength is Calculated

Entropy (measured in bits) represents the number of guesses an attacker would need. It is calculated from the length of your password and the size of the character set used. A password using only lowercase letters has a character set of 26; adding uppercase gives 52; numbers brings it to 62; symbols push it to 94+.

Modern GPUs can test billions of password guesses per second. A 60-bit entropy password would take centuries even on specialised hardware — while a 30-bit password might fall in seconds.