What Makes a Strong Password?
A strong password is long (12+ characters), uses a mix of uppercase and lowercase letters, numbers, and symbols, and avoids dictionary words, predictable patterns, and personal information. Password strength is measured by entropy — the number of bits required to describe all possible passwords of that length and character set. Higher entropy means exponentially more guesses needed to crack it.
How to Use
- Type your password into the field above (it stays in your browser — nothing is sent to any server).
- See the real-time strength bar, checklist, estimated crack time, and entropy score.
- Toggle Show to reveal the password as you type.
- Improve your password based on the checklist recommendations.
Frequently Asked Questions
A strong password is at least 12 characters long and includes a mix of uppercase letters, lowercase letters, numbers, and special symbols. It should not contain dictionary words, keyboard patterns (qwerty, 12345), or personal information like birthdays. A passphrase (4+ random words) can be both strong and memorable.
NIST recommends at least 8 characters, but security experts recommend 12–16 for typical accounts and 20+ for high-value accounts. Length dramatically increases security: a 12-character random password takes centuries to crack, while an 8-character password can be cracked in hours using modern hardware.
Password entropy (measured in bits) represents how unpredictable a password is. It's calculated as log₂(charset_size^length). A 12-character password using all character types (95 printable ASCII chars) has ~79 bits of entropy. Security experts generally recommend 60+ bits for most accounts and 80+ bits for sensitive accounts.
Yes — strongly recommended. Password managers (like Bitwarden, 1Password, or the built-in managers in browsers) generate and remember unique, strong passwords for every site. This eliminates the #1 security risk: password reuse. Never use the same password on two different sites — a breach of one site exposes all your accounts.