Security
Password Strength Checker
Verify your password entropy locally without network calls.
Input
Type a password to analyze its strength instantly.
This checker runs locally and does not transmit your input.
Strength
Enter a password to see the strength.
Frequently Asked Questions
What does the password checker evaluate?
Length is the most important factor — each additional character multiplies the brute-force search space exponentially. A 20-character password of random lowercase is stronger than a 12-character password with all character types. Combine length with variety: uppercase, lowercase, digits, and symbols.
How is password strength calculated?
Entropy (bits) = log2(charset size ^ length). A 12-character password using all character types (94 printable ASCII) has log2(94^12) ≈ 78 bits of entropy. Modern recommendations call for at least 80–100 bits for sensitive accounts. This tool also checks against common password patterns and dictionary words.
Why do some strong-looking passwords score low?
Passwords with predictable substitutions (P@ssw0rd, S3cur1ty!) are in attacker dictionaries as common patterns. A password's effective strength is reduced by its predictability even if it contains special characters. Truly random strings of average length beat predictable 'complex' patterns.