Strong Password Generator: Create Secure Passwords Free Online

Generate a strong password instantly

PDFSpot's free Password Generator creates cryptographically secure random passwords in your browser. No server connection, no data stored.

1. 1Go to the Password Generator tool above.
2. 2Choose your password length — 16 characters or more is recommended.
3. 3Select the character types: uppercase letters, numbers, and symbols for maximum strength.
4. 4Click Generate and copy your new password.
5. 5Store it in a password manager — never write it down or reuse it.

What makes a password strong?

A strong password has four key qualities:

Length — The longer the password, the harder it is to crack. Every additional character multiplies the number of possible combinations exponentially. 12 characters is the minimum; 16–20 is better.

Randomness — Predictable patterns ("Password1!") are easy for attackers to guess. True randomness — generated by a computer, not chosen by a human — is much harder to break.

Mixed character types — Using uppercase letters, lowercase letters, numbers, and symbols increases the character set from 26 to 95+ possible characters per position.

Uniqueness — Never reuse a password across multiple accounts. If one site is breached, all your other accounts are exposed.

How random password generators work

PDFSpot's generator uses the Web Crypto API (crypto.getRandomValues) — the same cryptographic randomness used by browsers for secure communications. This is fundamentally different from Math.random(), which is not cryptographically secure and should never be used for passwords. The entire generation happens in your browser: no password is ever sent to a server.

Password strength explained

Password strength is measured in "bits of entropy" — the number of possible combinations an attacker would need to try. Here is a rough guide:

8 characters, letters only — ~41 bits — crackable in minutes with modern hardware.

12 characters, mixed — ~79 bits — very strong for most purposes.

16 characters, mixed — ~105 bits — practically uncrackable.

20 characters, mixed — ~131 bits — overkill for everything except nation-state-level threats.

Aim for at least 80 bits of entropy for any account that matters.

Where to store your generated password

A strong password is useless if you write it on a sticky note or store it in a plain text file. Use a password manager:

Bitwarden — free, open source, cross-platform.

KeePass — free, local storage, maximum privacy.

1Password — paid, polished interface.

Apple Keychain / Google Password Manager — built into iOS/macOS/Android, free.

Password managers generate, store, and auto-fill passwords. You only need to remember one master password.

Common password mistakes to avoid

Avoid these common pitfalls that make passwords weak despite looking complex:

• ✓Substituting letters with look-alikes (p@ssw0rd) — attackers check these patterns first.
• ✓Using personal information: names, birthdays, pet names, addresses.
• ✓Reusing the same password or small variations across sites.
• ✓Using dictionary words, even with numbers added at the end.
• ✓Passwords under 12 characters, regardless of complexity.
• ✓Sharing passwords via email, SMS, or chat — use a secure vault sharing feature instead.