Password Generator
Generate strong, random passwords with customizable length and character types.
Create secure passwords for any account instantly.
What Makes a Strong Password A strong password has enough length and randomness that brute-force guessing is impractical. Each additional character multiplies the number of possible combinations exponentially. A 16-character password using letters, numbers, and symbols has roughly 95^16 (over 10^31) possible combinations.
Character Sets and Entropy Entropy measures the randomness of a password in bits. Each bit of entropy doubles the number of possibilities. A fully random password’s entropy = log2(character_set_size ^ length). For example, a 12-character password using all 95 printable ASCII characters has about 79 bits of entropy. Security experts recommend at least 60 bits for standard accounts and 80+ bits for sensitive accounts.
Character Set Sizes Lowercase letters (a-z) provide 26 characters. Adding uppercase (A-Z) brings the total to 52. Adding digits (0-9) reaches 62. Adding symbols (!@#$%^&*) reaches the full 95 printable ASCII characters. The more character types included, the higher the entropy per character.
Recommended Lengths For general accounts, 12-16 characters using mixed types is considered strong. For high-security accounts (banking, email), 16-20+ characters is recommended. Password managers can handle any length, so there is no practical reason to use short passwords. The generator below creates cryptographically random passwords using your browser’s built-in random number generator.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.