Password Generator, Create Strong Random Passwords

Password Generator

Generate a cryptographically strong random password in one click. Choose your desired length (8 to 64+ characters) and toggle which character types to include: uppercase letters, lowercase letters, numbers, and special symbols. The generator uses the Web Crypto API (crypto.getRandomValues), the same cryptographic randomness used by banks and security software, to ensure each character is selected with genuine unpredictability. A visual strength meter below the password shows its estimated resistance to brute-force attacks, based on the character pool size and length. A 12-character password with all four character types produces about 72 bits of entropy, which would take modern hardware centuries to crack by exhaustive search. Increasing length to 16+ characters pushes this into the "practically unbreakable" range. Click the generated password to copy it to your clipboard. The password is generated entirely in your browser, it is never sent to any server, never logged, and never stored. When you close or refresh the page, the password exists only wherever you pasted it.

How it works

The generator builds a character pool from the selected types (uppercase A-Z, lowercase a-z, digits 0-9, symbols !@#$%^&*...). It then creates a Uint8Array of the requested length and fills it with cryptographically random bytes using crypto.getRandomValues(). Each byte is mapped to a character from the pool using modular arithmetic to maintain uniform distribution. The strength meter calculates entropy as length times log2(pool size), for example, 16 characters from a 94-character pool gives about 105 bits of entropy. The password is displayed in a monospace font for readability, and clicking it triggers the Clipboard API to copy.

When to use this tool

Security-conscious users generate unique passwords for each online account to prevent credential stuffing attacks. System administrators create random passwords for service accounts and API keys. Developers generate test passwords for authentication system testing. Students learn about password entropy and brute-force resistance by experimenting with different lengths and character sets. Teams share randomly generated WiFi or meeting passwords for temporary access.

Frequently asked questions

Is this password generator secure enough for real use?

Yes. It uses crypto.getRandomValues(), which is the browser\'s cryptographic random number generator, the same source used for TLS encryption. The passwords are generated locally in your browser and never transmitted anywhere. For maximum security, use at least 16 characters with all four character types enabled.

What password length should I use?

For most accounts, 16 characters is an excellent choice, it provides over 100 bits of entropy with mixed character types. For critical accounts (banking, email master password), 20+ characters is even better. The minimum recommended length is 12 characters; anything below 10 is considered weak by modern standards.

Should I include special characters?

Yes, when the website allows them. Special characters dramatically increase the character pool (from 62 to 94+), which increases entropy by about 60% at the same length. Some sites restrict which symbols are allowed, if your password is rejected, try regenerating without symbols or with a longer all-alphanumeric password.

How is password strength calculated?

Strength is measured in bits of entropy: length multiplied by log2 of the character pool size. A 12-character password from a 94-character pool has about 79 bits. Below 40 bits is weak, 60-80 is moderate, 80-100 is strong, and above 100 is excellent. The strength bar reflects these thresholds.

Does this remember or store my passwords?

No. The password exists only in your browser\'s memory while the page is open. It is never sent to any server, never stored in a database, and never logged. When you close the tab, the password is gone from this tool. Always save generated passwords in a dedicated password manager.

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