Is my password sent to any server?
No. All analysis runs entirely in your browser. Your password is never uploaded, logged, or stored anywhere.
Password Strength Checker analyzes your password's security across multiple dimensions: length, character set diversity, entropy bits, estimated crack time, and vulnerability to common dictionary attacks and known breached password lists. Unlike simple "red/yellow/green" meters, this tool shows you exactly why a password is weak and what specific improvements will make it stronger.
Password strength is calculated using entropy bits (log2 of possible combinations based on character pool and length). Patterns like keyboard walks (qwerty, 12345), dictionary words (password, dragon), and common substitutions (@ for a, 0 for o) are detected and penalized, as attackers use these in rule-based attacks.
No. All analysis runs entirely in your browser. Your password is never uploaded, logged, or stored anywhere.
Because attackers use rule-based attacks that automatically test common words with letter substitutions. "P@ssw0rd" is in every modern password cracking ruleset and would be cracked quickly despite meeting basic complexity rules.
Entropy = log2(character pool size ^ password length). Example: a 12-character password using uppercase + lowercase + digits (62 chars) has log2(62¹²) ≈ 71 bits of entropy.
At least 16 characters with mixed types. With 16 characters from a 95-char pool, brute-forcing would take millions of years even with GPU clusters.
An estimate of how long it would take a modern GPU cluster (10 billion guesses/second) to crack the password using a brute-force attack.
Yes, completely free. No login or account required.
Tool workspace
Free password strength checker online — instantly test password security, entropy, and crack time estimate. See if your password is weak, medium, strong, or very strong. No login.
Input
password123
Output
Weak — crackable in seconds — dictionary word + numbers pattern detected