Password Generator
Generate a strong, random password with customizable length and character sets, along with an entropy-based strength estimate.
About this calculator
Generate a strong, random password with the exact length and character mix you choose, along with an estimate of how hard it would be to crack.
Every character generated uses the browser's cryptographically secure random number source (crypto.getRandomValues), not Math.random(), so the output isn't predictable the way a pseudo-random generator can be. Password strength here is estimated using Shannon entropy: the character pool size raised to the power of the password length, expressed in bits — more available character types and more characters both increase entropy, and therefore how many attempts a brute-force search would need.
How to use
- Choose a password length.
- Toggle which character types to include: uppercase, lowercase, numbers, and symbols.
- Optionally exclude visually ambiguous characters (like 0/O or l/1).
- Press Generate to create a new password and see its estimated entropy and strength rating.
Tips
- Longer passwords are far more effective than complex short ones — a 16-character password beats a 8-character one with symbols.
- Use a unique password for every account; a password manager makes this practical.
Formula
Entropy (bits) = length × log₂(character pool size)