Password Generator
Generate high-strength random passwords with customizable character types and length, using cryptographically secure random generation purely in your browser.
FAQ
Are the generated passwords secure?
Cat Toolbox's password generator uses the browser's built-in crypto.getRandomValues() cryptographically secure pseudorandom number generator (CSPRNG), consistent with the operating system's underlying cryptographic module. Generated passwords are unpredictable and far more secure than Math.random(). All processing happens locally in your browser; nothing is uploaded to any server.
How long should a password be?
Generally, passwords should be at least 12 characters long. A 12-character password containing uppercase letters, lowercase letters, and numbers has an entropy of about 71 bits, which is already quite secure. For important accounts (online banking, email, etc.), we recommend using 16+ characters including special symbols, achieving over 100 bits of entropy.
What is entropy?
Entropy is a mathematical measure of password strength, measured in bits. The higher the entropy, the harder the password is to brute-force. Each additional bit doubles the difficulty. Generally, entropy ≥ 60 bits is considered "strong", and ≥ 80 bits is "very strong".
Related guide
What the Password Generator and the Strength Checker Actually Compute
The generator rates your settings, the checker rates the string you type, and those two numbers are not comparable. Exact alphabet sizes (26/26/10/27), the four entropy bands, the 40-word common list, the crack-time model — plus the one unit label on the checker that is off by a factor of ten.