Free Developer Tool — 100% Client-Side

Password Generator

Name: Password Generator - WebUtil
Author: WebUtil

Generate strong, secure passwords with customizable length and character sets.

Password Length 20

4 128

Character Options

A–Z a–z 0–9 !@#$%

Generated Password

What Makes a Password Secure?

A secure password is the first line of defense against unauthorized access to your online accounts. The most strong passwords are long, random, and contain a mix of character types. Using a free password generator ensures you create truly random passwords that are resistant to brute-force attacks, dictionary attacks, and common guessing techniques. Our online password generator creates cryptographically secure passwords using the Web Crypto API, making each random password unique and unpredictable.

Password Strength Guidelines

Use at least 12 characters — Longer passwords are exponentially harder to crack. Aim for 16-20 characters when possible.
Mix character types — Combine uppercase letters, lowercase letters, numbers, and symbols to maximize entropy.
Avoid dictionary words — Do not use real words, common phrases, or keyboard patterns like qwerty or 123456.
Never use personal information — Avoid names, birthdates, addresses, or any information that could be found on social media.
Use a unique password for every account — Never reuse passwords across different websites or services.

How to Use This Password Generator

Using our secure password generator is simple. First, adjust the password length using the slider — longer passwords provide stronger security. Next, select the character types you want included: uppercase letters (A–Z), lowercase letters (a–z), numbers (0–9), and symbols (!@#$%). For maximum security, enable all four options. Click Generate Password to create a new strong random password. Review the strength meter to see how secure your password is, then use the Copy button to save it to your clipboard.

Tips for Managing Generated Passwords

Once you generate a strong password, use a password manager like 1Password, Bitwarden, or Apple Keychain to store it securely. Password managers encrypt your vault and can auto-fill credentials on websites, making it easy to use unique, complex passwords everywhere. Enable two-factor authentication (2FA) on all accounts that support it for an additional security layer. Never write passwords on sticky notes, save them in plain text files, or share them through email or messaging apps.

A strong random password generator is your first line of defense against credential stuffing, brute force attacks, and dictionary attacks across digital services. According to the National Institute of Standards and Technology (NIST SP 800-63B), the single most important factor determining password strength is length and entropy rather than complex arbitrary substitution rules. A 16-character password chosen uniformly from a 94-character set (uppercase, lowercase, numbers, and symbols) provides over 105 bits of cryptographic entropy: cracking it would take a modern high-performance GPU cluster billions of years. WebUtil's password generator uses the browser's native Web Crypto API (`window.crypto.getRandomValues`), which accesses the operating system's kernel-level cryptographically secure pseudo-random number generator (CSPRNG, such as /dev/urandom on Linux/macOS or CryptGenRandom on Windows). Crucially, all password generation happens entirely client-side on your local CPU. Passwords are never sent across a network, never logged on any server, and never cached. Once you close or reload the tab, the generated passwords vanish completely from memory.

How to Do This in Code

function generatePassword(len) {
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()';
  return Array.from(crypto.getRandomValues(new Uint32Array(len)))
    .map(v => chars[v % chars.length]).join('');
}

import secrets
import string
chars = string.ascii_letters + string.digits + '!@#$%^&*()'
password = ''.join(secrets.choice(chars) for _ in range(16))

import "crypto/rand"

func genPassword(n int) string {
  chars := []byte("ABC...xyz0129!@#$")
  b := make([]byte, n)
  rand.Read(b)
  for i := range b { b[i] = chars[b[i] % byte(len(chars))] }
  return string(b)
}

openssl rand -base64 12
< /dev/urandom tr -dc 'A-Za-z0-9!@#$' | head -c16

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Password Generator FAQ

How secure are passwords generated by WebUtil?

They are cryptographically secure. WebUtil utilizes the browser's Web Crypto API (crypto.getRandomValues), drawing randomness directly from your operating system's entropy pool.

What is password entropy and how many bits do I need?

Entropy measures unpredictability in bits. A password with 80+ bits is considered strong against offline attacks, while 100+ bits (achieved with a 16+ character random password) provides robust long-term defense.

What do the latest NIST SP 800-63B guidelines recommend?

NIST recommends prioritizing password length (at least 12-16 characters) over frequent expiration or forced symbol combinations, and checking against lists of known breached passwords.

Are passwords generated here ever sent over the network or saved?

Never. Generation runs entirely inside your browser's local memory. No passwords, timestamps, or telemetry are ever sent to WebUtil servers or third parties.

How long would it take a supercomputer to brute-force a 16-character password?

A random 16-character password with letters, digits, and symbols contains ~105 bits of entropy. At 100 trillion guesses per second, brute-forcing it would take hundreds of trillions of years.

Can I use this password generator offline?

Yes. Once this page is loaded in your browser, it operates fully offline without any internet connection.