Strong Password Generator — Passwords That Take Centuries to Crack

Generate passwords with enough entropy to withstand modern GPU cracking farms. See real-time strength analysis with crack time estimates for four attack scenarios.

Password Strength by the Numbers

Password strength is measured in bits of entropy. Each bit doubles the number of possible passwords an attacker must try. Here's what different entropy levels mean in practice:

Under 40 bits: Cracked in seconds to minutes. Common passwords, short PINs, simple patterns.

40-59 bits: Cracked in hours to days. Short passwords with mixed character types.

60-79 bits: Cracked in years to decades. Moderate random passwords, 5-word passphrases.

80-127 bits: Cracked in centuries to millennia. Strong random passwords, 6-7 word passphrases.

128+ bits: Effectively uncrackable. Beyond brute force capability of any known technology.

Why 16+ Characters Is the New Baseline

In 2020, 8 characters was considered acceptable. By 2025, GPU cracking speeds have made 8-character passwords trivially breakable. NIST, OWASP, and security researchers now recommend 16 characters minimum for important accounts. Our generator defaults to 16 characters with all character types — providing approximately 105 bits of entropy. That would take longer than the age of the universe to crack with current technology.

A strong password is already generated below — copy it or customize the settings.

🔒 100% Client-Side🚫 No Data Stored🛡️ CSPRNG Secured📡 Zero Server Calls
Very Weak
Entropy: 0.0 bits

Security Tips

Use a unique password for every account

If one account gets breached, every account sharing that password is compromised. A password manager makes this practical.

Length beats complexity

A 20-character password with just lowercase letters is stronger than an 8-character password with all character types. When in doubt, make it longer.

Passphrases are your friend

Random word combinations are both strong and memorable. Use 5+ words for serious security. Great for master passwords you type frequently.

Never reuse passwords

Data breaches happen constantly. If your email and bank share a password, one breach exposes both. Use a password manager.

Enable two-factor authentication (2FA)

Even the strongest password can be phished. 2FA adds a second layer requiring physical access to your phone or security key.

How Password Generation Works

This tool uses your browser's built-in Cryptographic Random Number Generator (CSPRNG) — specifically crypto.getRandomValues() — to generate passwords. This is the same source of randomness used by operating systems, encryption software, and professional security tools.

For random passwords: The tool builds a character pool from your selected options, then picks characters using the CSPRNG. A Fisher-Yates shuffle ensures required characters are distributed randomly throughout.

For passphrases: Words are selected from the EFF's curated wordlist of 7,776 common English words. Each word adds approximately 12.9 bits of entropy.

For strength checking: We use zxcvbn, an open-source library from Dropbox that detects dictionary words, common names, dates, keyboard patterns, l33t speak, and repeated characters — simulating how attackers actually crack passwords.

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