12-character password generator

Generate random 12-character passwords from 86 characters: capital and small letters, numbers and special characters. Each password has about 77 bits of entropy.

Settings

Type
characters

From 4 to 128 characters.

Characters to include

Generated passwords

Please complete the details. The result will appear here.

How it is calculated

  1. Random numbers come from the browser's Web Crypto interface (crypto.getRandomValues), which is designed for security uses such as passwords. Values that would make some characters more likely are discarded, so every character has the same chance.
  2. A random password first takes one character from each selected type, fills the rest from all allowed characters, and then shuffles them. Each selected type therefore appears at least once, in a random position.
  3. Each digit of a PIN is chosen at random from 0 to 9, about 3.3 bits per digit.
  4. Entropy = length × log₂(number of allowed characters). The default letters, numbers and special characters make 86 characters, so 16 characters give about 102 bits.
  5. All calculations are done in your browser. The details you enter are not sent to any server.

Official sources

Applies to: NIST SP 800-63B-4 (July 2025); CISA guidance.

  1. National Institute of Standards and Technology: SP 800-63B-4, Digital Identity Guidelines: Authentication and Authenticator Management (section 3.1.1, Passwords)
  2. Cybersecurity and Infrastructure Security Agency: Use Strong Passwords (archived page)

Last reviewed on October 26, 2026.

The rules on this page have been checked against the official sources listed above. The result is for reference. The rules and assessment of the concerned authority shall prevail.