Strong Password Generator – Free Secure Password Maker

Generate a strong, random password — or a memorable passphrase — in one click. This free password generator uses cryptographically secure randomness, a visual entropy-based strength meter, and runs 100% locally: everything is generated in your browser and never leaves it.

🔒 Private by design: every password and passphrase is generated on your device with crypto.getRandomValues and never leaves your browser — no servers, no logs, no tracking, no storage.

How to Use the Password Generator

Pick a mode first: Random password for maximum strength, or Passphrase for something you can actually type from memory. In random mode, drag the length slider (8–64 characters; 16 is the default and a good choice for most accounts), tick the character types you want — uppercase, lowercase, digits and symbols — and press Generate Password. Every password is guaranteed to contain at least one character from each selected set, so you never get a "symbols required" rejection from a picky site. In passphrase mode, choose 4–6 words, a separator, and whether to capitalize each word, then press Generate Passphrase. The Copy button copies the result straight to your clipboard.

Below the result, the strength meter shows a color-coded bar — red, orange, yellow or green — rating your password Weak, Fair, Good or Strong based on its entropy in bits, a real mathematical measure, not a guess. If a site restricts which characters you can use (some banks disallow symbols), untick symbols and push the length up to compensate; length beats character variety every time. And remember: everything on this page runs locally — your passwords never leave your browser.

How It Works: Randomness and Entropy

Two things make a password strong: unpredictability and size. Unpredictability comes from crypto.getRandomValues, the browser's cryptographically secure random number generator — the same class of randomness used for encryption keys, far stronger than the basic Math.random() that many toy generators use. Size is measured as entropy:

With all four character sets selected, the pool is 26 + 26 + 10 + 32 = 94 characters. A 16-character password therefore has 16 × log₂(94) = 16 × 6.55 ≈ 104.9 bits of entropy — about 10³¹ possibilities. Each additional bit doubles the attacker's work, so 105 bits is roughly a billion times harder to brute-force than 75 bits. Ratings: under 40 bits is Weak, 40–60 Fair, 60–80 Good, and 80+ Strong.

Worked Example

Compare three password strategies by their entropy:

The last row is the punchline: a 20-character all-lowercase password (94 bits) beats a 12-character complex one (79 bits). When a site bans symbols, don't settle for 8 characters — go longer instead.

Passphrase vs Password — Which Should You Use?

A passphrase is a sequence of random words, like "correct-horse-battery-staple" — use the Passphrase mode above to generate one instantly from the built-in 120-word list. Each word adds about 6.9 bits of entropy (log₂ 120), so a 6-word passphrase carries roughly 41 bits: easy to type, fine for everyday logins, but weaker than a 16-character random password (~105 bits). The honest answer is to use both, for different jobs:

Whatever you choose, the rules that actually matter: never reuse passwords across sites, turn on two-factor authentication everywhere it is offered, and store random passwords in a reputable password manager rather than your memory or a notes app. A unique 105-bit password per site means one breached site can never cascade into your email and bank accounts.

Limitations

A strong password is one layer, not a complete defense: phishing, malware and SIM-swap attacks bypass password strength entirely, which is why two-factor authentication matters more than squeezing out extra bits. The generator needs a modern browser with crypto.getRandomValues (universal since ~2015); on truly ancient browsers it will not run. Entropy assumes a brute-force attacker — it does not protect against a password you have used elsewhere, written on a sticky note, or shared over WhatsApp. Generate on the device you'll use, store in a manager, and never share.

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