Password Generator
Generate secure, random passwords with entropy analysis and crack time estimates
📊 Entropy Analysis
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Free Password Generator — Strong, Random & Secure
Generate cryptographically strong passwords and passphrases with real-time entropy analysis and crack time estimates. Three generation modes: fully random, pronounceable, and multi-word passphrase. All processing is done locally — no passwords leave your browser.
3 Password Generation Modes
- Random — Fully random characters from your chosen character set. Highest entropy per character. Best for use with a password manager.
- Pronounceable — Alternates consonants and vowels to create memorable syllables like "bavokelitu". Easier to read aloud or type on mobile.
- Passphrase — Multiple random words joined by a separator. Example: "Maple-Cloud-River-Tiger". High entropy + easy to remember = ideal for master passwords.
Password Length Guide by Account Type
- Low-risk accounts (forums, newsletters) — 12 characters minimum
- Standard accounts (social media, shopping) — 16 characters
- High-security accounts (email, banking) — 20+ characters
- Master passwords (password manager) — 4–6 word passphrase
- Crypto & financial keys — 24+ characters with all character types
Understanding Entropy
Password entropy measures the unpredictability of a password in bits. Every additional bit doubles the number of possible passwords. At 10 billion guesses per second:
- 40 bits — Cracked in about 2 minutes
- 60 bits — ~36 years to crack
- 80 bits — ~37 million years
- 100 bits — Effectively uncrackable
Password Security Best Practices
- Never reuse passwords across different sites
- Store generated passwords in a password manager (Bitwarden, 1Password)
- Enable two-factor authentication (2FA) wherever possible
- Change passwords immediately if a data breach is detected
Frequently Asked Questions
How long should my password be?
For online accounts, use at least 12-16 characters. For high-security needs (crypto wallets, master passwords), use 20+ characters. Longer passwords exponentially increase cracking time. A 16-character random password would take centuries to crack at 10 billion guesses per second.
What makes a strong password?
Strong passwords are: long (16+ characters), random (not dictionary words), unique (never reused), and contain mixed character types. The best passwords combine uppercase, lowercase, numbers, and symbols. Use our entropy meter - aim for 60+ bits for good security.
Are passphrases better than passwords?
Passphrases (4-6 random words) can be both secure and memorable. A 4-word passphrase has roughly 44 bits of entropy, while a 6-word passphrase has 66 bits. They're easier to type and remember than random characters, making them ideal for master passwords.
How is password entropy calculated?
Entropy = length × log₂(charset_size). For example, a 12-character password using 62 characters (a-z, A-Z, 0-9) has 12 × log₂(62) ≈ 71 bits of entropy. Higher entropy means more possible combinations, making the password harder to crack through brute force.
What is a pronounceable password?
Pronounceable passwords alternate consonants and vowels to create syllable-like patterns (e.g., 'bavokelitu'). They're easier to say aloud and remember than fully random strings, while still being harder to crack than dictionary words. Good for situations where you need to type or dictate a password.
Should I use a password manager?
Yes, absolutely. Password managers (1Password, Bitwarden, Dashlane, KeePass) store unique, randomly-generated passwords for every site. You only need to remember one master password. Use this generator to create strong passwords for your accounts, then store them in your password manager.
What is 'Exclude Ambiguous Characters'?
Ambiguous characters like 0 (zero) and O (uppercase o), or 1 (one) and l (lowercase L) and I (uppercase i) look similar in many fonts. Excluding them prevents transcription errors when you need to type a password manually, especially on mobile or when reading from a screen.
Is it safe to generate passwords in a browser?
Yes. This tool generates passwords using JavaScript's Math.random() combined with the character set on your local device. No passwords are ever transmitted to our servers. The page runs entirely client-side — you can even use it offline.
What does 'Very Strong' mean on the strength meter?
The strength meter uses entropy to classify passwords: below 40 bits is Weak, 40–60 bits is Fair, 60–80 bits is Strong, and 80+ bits is Very Strong. Aim for at least 60 bits for most online accounts and 80+ bits for critical accounts like banking, email, and password manager master passwords.
How long would it take to crack my password?
The crack time estimate assumes a powerful attacker making 10 billion guesses per second — equivalent to state-level hardware. A 16-character random password (uppercase + lowercase + numbers + symbols) has ~98 bits of entropy and would take longer than the age of the universe to crack with brute force.