Security Tool

Password Generator

Generate cryptographically secure random passwords — custom length, character sets, passphrases, and bulk export. Everything runs in your browser, nothing is ever sent to a server.

16 ~95 bits
4 32 64 96 128
Your Password
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All passwords are generated using crypto.getRandomValues() in your browser — nothing is ever transmitted to a server.

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What Makes a Strong Password?

Password Entropy — The Real Measure of Strength

Strength is best measured in bits of entropy, not just length or complexity. Entropy quantifies the number of possible guesses an attacker must make: every bit doubles the search space. A password with 60 bits of entropy has over one quintillion possible values — far beyond what any brute-force attacker can realistically crack today.

The formula: entropy = length × log₂(charset size). A 12-character password from 94 printable ASCII characters has ~78 bits. Adding just 4 more characters pushes it to ~104 bits.

Random Passwords vs Passphrases

Random character passwords are maximally dense — short strings pack enormous entropy. A 20-character random password from the full charset has ~131 bits of entropy, essentially uncrackable forever. The downside: they're hard to memorize.

Passphrases (e.g. Correct-Horse-Battery-Staple) sacrifice some density for memorability. A 5-word passphrase from a 7,776-word Diceware list has ~64 bits. Both approaches are excellent; choose based on whether you need to type it from memory.

Common Password Mistakes to Avoid

  • Dictionary words — cracking tools test millions of words and variations per second
  • Predictable substitutions — p@ssw0rd is one of the first patterns attackers try
  • Personal information — birthdays, names, and pet names appear in credential dumps
  • Short passwords — anything under 12 characters is vulnerable to hardware-accelerated brute force
  • Password reuse — one breach exposes every account that shares the password
  • Incremental changes — Password1 → Password2 is trivially guessable

How to Store and Manage Generated Passwords

The only realistic way to use unique, strong passwords across many accounts is a password manager (Bitwarden, 1Password, KeePass). These store all credentials encrypted behind a single master password — you only need to remember one passphrase.

For developers storing user passwords in a database, never store plaintext or simple SHA hashes. Always use a proper password hashing function. Use our Bcrypt Hash Generator for secure server-side password storage, or check OWASP's Password Storage Cheat Sheet for Argon2id recommendations.

Frequently Asked Questions

Yes — this tool uses crypto.getRandomValues(), the browser's cryptographically secure pseudorandom number generator (CSPRNG). This is the same API used by browser-based cryptography and is seeded from hardware entropy sources (CPU timing, mouse movement, etc.). It is fundamentally different from Math.random(), which is not cryptographically secure. The passwords generated here have the same quality of randomness as passwords generated by professional security tools.
For online accounts, 16 characters using mixed case, numbers, and symbols provides around 105 bits of entropy — well beyond practical cracking. For sensitive accounts (email, banking, password manager master password), go to 20+ characters. For Wi-Fi passwords that are rarely typed, use 32 characters. The NIST 2024 guidelines emphasize length over complexity: a 20-character lowercase-only random password is stronger than a 12-character mixed-case one.
A 5-word Diceware passphrase has about 64 bits of entropy — strong enough for most purposes but somewhat weaker than a 16-character random password (~105 bits). The key is that the words must be truly random (not personally meaningful phrases like "IlovePizza"). The major advantage is memorability; the major risk is that many people cheat and pick familiar phrases, which have far less entropy than truly random selections. For a master password you'll type daily, a 6-word passphrase with a number and symbol is an excellent choice.
Certain characters look nearly identical in many fonts: the digit zero (0) and uppercase O (O), the digit one (1), lowercase L (l), and uppercase I (I). When reading or typing a password, these are easy to confuse. Enabling this option removes them from the character pool. This slightly reduces entropy (typically by 1–2 bits), which is negligible, while eliminating a major source of human error when transcribing passwords.
Absolutely — this is one of the most important password hygiene practices. When a service gets breached and credentials are leaked, attackers immediately try those username/password combinations against other major services (credential stuffing). If you reuse passwords, a breach at a low-security forum could compromise your bank account. With a password manager, using a unique 20-character random password for every account has no practical overhead — you never need to remember any individual password.
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