Random Password Generator

What Is a Random Password Generator?

// Generate a random password in JavaScript
function generatePassword(length, charset) {
  const array = new Uint32Array(length);
  crypto.getRandomValues(array);
  return Array.from(array, v => charset[v % charset.length]).join('');
}

// Example: 16-char password with all types
const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*';
generatePassword(16, chars);
// → 'kX#9mP$2vL!nQ7wR' (random each time)

Key Features

Examples

kX#9mP$2vL!nQ7wR&bZ4fG@8sY^5jD*3

Tm$8kR!pN3vZ@5qW

kRm4nTp7sWx2

Hx$4mR!pN3vZ@5qWtB2j
Yk#7wL&8sF^9gQ*2dXnR
Pr@6bT$3cN!5hJ^8mKvZ
Wq*9fG#2nS!7yD@4xLpM
Zv&3kR$8tH!6jB@5wNcQ

How to Use

1. 1

   Configure Your Password

   Use the length slider (4–128 characters, default 16) and toggle which character types to include: uppercase letters, lowercase letters, digits, and symbols. Optionally exclude ambiguous characters like 0, O, l, and 1.

2. 2

   Generate Passwords

   Click the Generate button. You can generate 1 to 50 passwords at once. Each password is created using your browser's cryptographic random number generator for maximum security.

3. 3

   Review Strength

   Check the strength indicator below each password. It shows the entropy in bits and estimated brute-force crack time, so you know exactly how secure your password is.

4. 4

   Copy and Use

   Click the Copy button next to any password to copy it to your clipboard. Use Copy All to grab every generated password at once.

Common Use Cases

Account Registration

Create a unique, strong password every time you sign up for a new website or app. Avoid reusing passwords across accounts.

Password Manager Seeding

Generate high-entropy passwords to store in your password manager. Start with the strongest possible passwords for all your accounts.

Enterprise & IT Security

Generate secure passwords for databases, servers, API keys, and service accounts that meet corporate security policies.

Development & Testing

Quickly generate test passwords for development environments, mock user accounts, and automated testing scenarios.

Wi-Fi & Network Security

Create strong WPA2/WPA3 keys for your wireless network. A 20+ character random password makes brute-force attacks impractical.

Technical Details

Web Crypto API

Uses crypto.getRandomValues() with Uint32Array for cryptographically secure random number generation. This API is available in all modern browsers and uses the operating system's CSPRNG (Cryptographically Secure Pseudo-Random Number Generator).

Entropy Calculation

Entropy = log₂(pool_size) × password_length. Pool sizes: lowercase (26), uppercase (26), digits (10), symbols (32). All four enabled: pool = 94 characters, giving ~6.55 bits per character. A 16-character password: ~104.9 bits.

Crack Time Estimation

Estimated brute-force time assumes 10¹² (1 trillion) guesses per second, which represents a high-end dedicated cracking rig. Formula: time = 2^entropy / guesses_per_second. Displayed in human-readable units (seconds to billions of years).

Best Practices

Use a Unique Password for Every Account

Never reuse passwords across different sites. If one site is breached, reused passwords give attackers access to all your other accounts. Use this generator to create a unique password for each account and store them in a password manager.

Aim for 16+ Characters

Longer passwords are exponentially harder to crack. A 16-character password with all character types would take billions of years to brute-force. For high-security accounts, use 20–32 characters.

Enable All Character Types

Using uppercase, lowercase, digits, and symbols maximizes the character pool and entropy per character. Only disable character types when a site's password rules require it.

Use a Password Manager

You cannot memorize dozens of unique random passwords. Use a password manager (Bitwarden, 1Password, KeePass) to store them securely. Then you only need to remember one strong master password.

Frequently Asked Questions