Random Password Generator – Secure Passwords Online

  • Adam
  • November 2, 2025

Generate secure random passwords, passphrases & 128-bit encrypted passwords instantly. Customize length, symbols & character types. Free online password maker.

🔐 Random Password Generator

Create Secure & Unique Passwords Instantly

Random Password

Generate completely random passwords with customizable length and character types.

Secure Password

Create high-entropy passwords with additional security features and character requirements.

Passphrase

Generate memorable passphrases using random dictionary words separated by symbols.

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Your Random Password
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Understanding Password Generation

Random Password Generator

A random password generator creates completely randomized character sequences by selecting characters from a defined character set. Each character is chosen independently, making the password unpredictable and highly secure against dictionary attacks.

Character Set Formula:

Entropy = log₂(Character Set Size) × Password Length

Example Calculation:

16-Character Password with All Character Types
Character Set: 26 uppercase + 26 lowercase + 10 numbers + 32 symbols = 94 characters
Entropy: log₂(94) × 16 = 6.55 × 16 = 104.8 bits
Example Output: K9@mL#2xQ!pR$4vT

Common Use Cases:

• Bank accounts and financial services
• Email accounts and password managers
• Administrative and root account passwords
• Enterprise security systems

Secure Password Generator

Secure password generators create passwords with guaranteed minimum requirements for maximum security. They ensure at least one character from each character type (uppercase, lowercase, numbers, symbols) and typically use a minimum length of 12 characters for enhanced security.

Security Requirements:

Min Entropy = 128 bits (recommended by NIST)
Password Strength = ✓ Mixed Case + ✓ Numbers + ✓ Symbols + ✓ 12+ Characters

Example Secure Passwords:

8-Character Secure Password Examples
Pw1@xQ9$ | Mx8#nL2K | Bv5!pT7Y | Rc3$hW6J
16-Character Secure Password Examples
M9kL@2x#pQ5!vR8T | B7cN$4w&dF2%sJ6X | P3qR!8h*jK1$nM5o

Security Benefits:

• Protects against brute-force attacks (2^128+ possibilities)
• Prevents dictionary attacks through special characters
• Meets most enterprise password policies
• NIST SP 800-63B compliant

Passphrase Generator

Passphrase generators create passwords using random dictionary words separated by special characters. These are easier to remember than random character strings while maintaining high security through the combination of word count and special separators.

Passphrase Strength Formula:

Entropy = log₂(Dictionary Size) × Number of Words
Typical: log₂(10,000) × 4 words = 13.3 × 4 = 53.2 bits

Example Passphrases:

4-Word Passphrase Examples
Purple-Elephant-Mountain-Thunder
Silver-Ocean-Dragon-Whisper
Bright-Garden-Phoenix-Castle
Dancing-Thunder-Mystic-River
With Capitals, Numbers & Symbols
Purple-Elephant9-Mountain!-Thunder#
Silver5-Ocean-Dragon@-Whisper2
Bright-Garden$-Phoenix8-Castle!

Advantages of Passphrases:

• Easier to remember than random strings
• High entropy with fewer characters
• Less prone to typos
• Suitable for offline storage in password managers

Password Length Guide

Recommended Lengths by Use Case:

8-Character Password
Entropy: ~53 bits
Use: Social media, shopping sites, low-security accounts
Example: Ax9@Kl3m
12-Character Password
Entropy: ~80 bits
Use: Email accounts, moderate security
Example: B7mN@2xPq5!R
15-Character Password
Entropy: ~99 bits
Use: Banking, financial accounts
Example: K9@wL#3tM!pY$5vX
16-Character Password
Entropy: ~104 bits
Use: High-security, administrative accounts
Example: R7&xJ#2pM!9qK$5w

NIST Guidelines (SP 800-63B):

✓ Minimum 8 characters for general use
✓ 12+ characters recommended for critical accounts
✓ 16+ characters for highest security levels
✓ Consider passphrase length, not just character count

Comparison with Popular Tools

Google Random Password Generator:

Google's built-in password generator (available in Chrome and Google Account settings) creates 16-character alphanumeric passwords with symbols. It integrates with Google's password manager and syncs across devices. Our generator offers more customization options including passphrase generation.

Key Differences:

Feature Comparison
Our Generator:
✓ Customizable length (8-128 characters)
✓ Passphrase generation
✓ Character type selection
✓ Works offline
✓ No account required

Google Generator:
✓ Fixed length (16 characters)
✓ Cloud sync capability
✓ Integration with Chrome
✓ Account-linked storage

Frequently Asked Questions

What makes a password secure?
A secure password has three key characteristics: (1) Sufficient length (12+ characters minimum), (2) Character diversity (mix of uppercase, lowercase, numbers, and symbols), and (3) Randomness (unpredictable patterns). The strength is measured in bits of entropy. For example, a 16-character password with all character types provides approximately 104 bits of entropy, making it resistant to brute-force attacks.
How long does it take to crack passwords?
Cracking time depends on entropy and computing power. An 8-character password with symbols can be cracked in hours. A 12-character password takes days to weeks. A 16-character password would take years, and a 20+ character password is considered practically uncrackable with current technology. This assumes online attacks without rate limiting; offline attacks are faster but require database access.
Should I use the same password everywhere?
Never reuse passwords. If one service is breached, attackers gain access to all your accounts using that password. Always generate unique passwords for each account. Password managers like 1Password, LastPass, or Bitwarden can store and autofill unique passwords securely.
Is it safe to use online password generators?
Modern online password generators are safe if they use client-side generation (JavaScript running on your device). Your passwords are generated locally and never sent to any server. Always use HTTPS connections and ensure the generator does not log or store passwords. This tool generates passwords entirely in your browser.
What is password entropy?
Entropy measures password unpredictability. It's calculated as: Entropy (bits) = log₂(possible outcomes). For passwords: Entropy = log₂(character set size) × length. Example: A 12-character password using 94 possible characters has entropy of log₂(94) × 12 ≈ 79 bits. Higher entropy means stronger passwords. NIST recommends minimum 128 bits for critical accounts.
Can I use symbols in all password fields?
Most modern web applications support symbols in passwords, but some legacy systems don't. If a website rejects your password, it usually shows an error. Common unsupported symbols vary by platform. For critical accounts (email, banking), use symbols. For older systems, try numeric/alphanumeric passwords. Always check the website's password requirements before generating.
How often should I change my passwords?
NIST SP 800-63B recommends changing passwords only when compromised, not on a schedule. Regular changes were required historically but are no longer considered necessary. However, change passwords immediately if: (1) A service is breached, (2) You use the password on multiple sites, (3) An unauthorized person may have learned it, or (4) The account handles sensitive information.
What is a passphrase and why use it?
A passphrase is a sequence of random words separated by symbols, like "Purple-Mountain-Thunder-Ocean". Passphrases offer two advantages: (1) Easy to remember compared to random characters, and (2) High entropy through word combinations. A 4-word passphrase typically provides ~52 bits of entropy, equivalent to a 10-character random password.
What are the most common password mistakes?
Common mistakes: (1) Using personal information (names, birthdates), (2) Sequential characters or patterns (abc123), (3) Dictionary words without symbols, (4) Reusing passwords across sites, (5) Storing passwords in plain text, (6) Using short passwords (<8 characters), (7) Sharing passwords via email or chat. Always use generated random passwords and store them in a password manager.
How do I store generated passwords securely?
Use a password manager - they encrypt and securely store passwords. Top options: (1) Bitwarden - open-source, free with premium options, (2) 1Password - premium, excellent UI, (3) LastPass - popular, free version available, (4) KeePass - offline-first, no cloud. Never store passwords in plain text files, browser autocomplete, or sticky notes.

🔗 Official Sources & References

NIST Special Publication 800-63B: Authentication and Lifecycle Management https://pages.nist.gov/800-63-3/sp800-63b.html

Official NIST guidelines on password requirements, entropy, and security best practices.

Microsoft Password Guidance https://docs.microsoft.com/en-us/microsoft-365/business-premium/sign-in-secure-password

Microsoft's recommendations for password security and best practices.

OWASP Password Storage Cheat Sheet https://cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html

OWASP guidelines for securely storing and hashing passwords.

FBI and CISA Password Security Guidelines https://www.cisa.gov/secure-our-world/secure-people/protect-yourself

U.S. government recommendations on password security and cyber threats.

Google Account Password Guidelines https://support.google.com/accounts/answer/32040

Google's official recommendations for creating strong passwords.

EFF Password Security Article https://www.eff.org/deeplinks/2016/07/password-tips-and-tricks

Electronic Frontier Foundation's comprehensive guide to password security.

Bitwarden Password Generator https://bitwarden.com/password-generator/

Popular open-source password manager with built-in generation tools.

1Password Security Best Practices https://support.1password.com/strong-security/

1Password's guide to creating and managing secure passwords.

Entropy and Password Strength (Wikipedia) https://en.wikipedia.org/wiki/Password_strength

Comprehensive overview of password entropy and strength calculations.

Have I Been Pwned - Check Data Breaches https://haveibeenpwned.com/

Check if your passwords or email have been compromised in known data breaches.

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