What Makes a Strong Password?
A strong password is your first line of defense against unauthorized access. The strength of a password depends on its length, character diversity, and randomness. Passwords that use a mix of uppercase letters, lowercase letters, numbers, and symbols are exponentially harder to crack than simple alphabetic passwords.
For example, an 8-character password using only lowercase letters has about 268 (approximately 209 billion) possible combinations. Add uppercase letters, digits, and symbols and the pool grows to over 95 characters, yielding 958 (about 6.6 quadrillion) combinations -- over 30,000 times harder to brute-force.
Security experts recommend a minimum of 12-16 characters for important accounts. For maximum security, use 20+ characters with all character types enabled. Never reuse passwords across sites, and consider using a password manager to store them securely.
Understanding Password Entropy
Entropy is a measure of randomness or unpredictability in a password, expressed in bits. It is calculated as E = L x log2(R) where L is the password length and R is the size of the character pool.
Higher entropy means the password is harder to guess. Here is a rough guide:
| Entropy (bits) | Strength | Use Case |
|---|---|---|
| < 28 | Weak | Never recommended |
| 28-35 | Fair | Low-value throwaway accounts |
| 36-59 | Good | General online accounts |
| 60-79 | Strong | Email, banking, important accounts |
| 80+ | Very Strong | Master passwords, encryption keys |
Password Security Tips
Use unique passwords
Never reuse the same password across multiple sites. A breach on one site would compromise all your accounts.
Enable two-factor authentication
Even the strongest password benefits from a second layer of verification, such as an authenticator app or hardware key.
Use a password manager
Password managers securely store hundreds of unique passwords so you only need to remember one master password.
Avoid personal information
Never use names, birthdays, pet names, or common words. Attackers use social engineering to guess these first.
Longer is stronger
Each additional character exponentially increases the time needed to crack your password. Aim for 16+ characters.
Check for breaches
Use services like Have I Been Pwned to check if your email or passwords have appeared in known data breaches.
Frequently Asked Questions
Yes. Passwords are generated entirely in your browser using the Web Crypto API (crypto.getRandomValues). No passwords are ever sent to a server, stored, or logged. You can verify this by checking your browser's network tab -- zero requests are made during password generation.
Entropy measures how unpredictable a password is, expressed in bits. It is calculated as length multiplied by log2 of the character pool size. Higher entropy means the password is exponentially harder to guess. A password with 80+ bits of entropy is considered very strong for most purposes.
Security experts recommend at least 12 characters for most accounts and 16+ characters for sensitive accounts like email, banking, and master passwords. The longer the password, the more resistant it is to brute-force attacks. Our generator supports up to 128 characters.
Adding symbols and numbers increases the character pool size, which exponentially increases the number of possible password combinations. An 8-character password with only lowercase letters has about 209 billion combinations, but adding uppercase, numbers, and symbols increases this to over 6.6 quadrillion.
Ambiguous characters are those that look similar and can cause confusion when reading or typing a password: the number 0 and the letter O, the number 1, the lowercase L (l), and the uppercase I. Excluding them makes passwords easier to type manually without sacrificing meaningful security.
Crack time is estimated assuming an attacker can test 10 billion password guesses per second (a high-end GPU cluster). The total time is calculated as 2^entropy divided by the guess rate. Real-world crack times depend on the attack method, hardware, and whether the password hash is salted.
Absolutely. A password manager lets you use a unique, strong, randomly generated password for every account without memorizing them. You only need to remember one strong master password. Popular options include Bitwarden, 1Password, and KeePass.
Yes. Use the Bulk Generate section to create up to 100 passwords at once with your current settings. All generated passwords can be copied to your clipboard with a single click using the Copy All button.