Generate cryptographically secure passwords instantly. 100% client-side — nothing is ever sent to a server.
Strong Password Generator — Free & Secure
This password generator uses the Web Crypto API (crypto.getRandomValues()) to generate cryptographically secure random passwords. Unlike Math.random(), the Crypto API provides true randomness that cannot be predicted or reproduced.
What makes a strong password?
- At least 16 characters long (20+ is recommended)
- Mix of uppercase, lowercase, numbers and symbols
- No dictionary words or predictable substitutions (p@ssw0rd is not secure)
- Unique — never reused across multiple accounts
- High entropy — measured in bits (128+ bits is considered strong)
Password entropy explained
Entropy measures how unpredictable a password is. A 20-character password using all character types has ~131 bits of entropy. Even the fastest computers cannot brute-force 128-bit entropy passwords in any practical timeframe.
Frequently Asked Questions
Are these passwords safe to use? +
Yes. This tool uses the browser's built-in Crypto API (crypto.getRandomValues) which is cryptographically secure. Your passwords are generated entirely on your device and never transmitted anywhere.
How long should my password be? +
For most accounts, 16–20 characters is excellent. For highly sensitive accounts (banking, email, password manager master password), use 24–32 characters. Never go below 12 characters for any important account.
Should I use a password manager? +
Absolutely. Use a password manager like Bitwarden, 1Password, or Dashlane to store unique strong passwords for every account. Never reuse passwords — a single breach can compromise all your accounts if you do.
What is entropy and why does it matter? +
Entropy measures password strength in bits. Each bit doubles the number of guesses required to crack it. 64 bits = 18 quintillion guesses. 128 bits = 340 undecillion guesses. Modern GPUs can try ~10 billion passwords/second, so 128+ bit entropy is effectively uncrackable.