Password Generator

安全で強力なパスワードを即座に生成。

Very Strong

Length16

Uppercase (A-Z)Lowercase (a-z)Numbers (0-9)Symbols (!@#$)

Cryptographically Secure

Uses the Web Crypto API's crypto.getRandomValues() — the same source used by your operating system's security functions.

Fully Customizable

Adjust length from 4 to 64 characters. Toggle uppercase letters, lowercase letters, numbers, and special symbols independently.

Strength Meter

A real-time visual indicator rates your password from Weak to Very Strong based on length, character variety, and complexity.

Private & Client-side

Passwords are generated entirely in your browser. No passwords are ever sent to or stored on our servers.

Password Generatorについて

A strong password is your first line of defense against unauthorized access to your accounts. Our Password Generator uses your browser's built-in cryptographic random number generator — the same technology used in professional security software — to create passwords that are genuinely unpredictable. You can generate passwords up to 64 characters long, choosing any combination of uppercase letters, lowercase letters, digits, and special characters. The strength indicator evaluates your password across multiple dimensions: length, character variety, and entropy, giving you an immediate visual signal of how secure the generated password is.

Password Generatorの使い方

Set your desired password length using the slider — 16 characters is the recommended minimum for most accounts.
Check or uncheck character types: uppercase letters (A-Z), lowercase letters (a-z), numbers (0-9), and symbols (!@#$...).
Click "Generate New Password" to create a new cryptographically random password with your selected settings.
Review the strength indicator — aim for "Strong" or "Very Strong".
Click "Copy" to copy the password to your clipboard, then paste it directly into your password manager or account.

よくある質問

How secure is this password generator?

It uses crypto.getRandomValues() from the Web Crypto API, which is a cryptographically secure pseudo-random number generator (CSPRNG). This means passwords cannot be predicted even if an attacker knows previous outputs, making them suitable for protecting sensitive accounts.

Are my generated passwords stored anywhere?

No. All password generation happens entirely in your browser using JavaScript. No data is sent to any server, and no passwords are logged or stored. The moment you close the page, the generated passwords are gone.

How long should my password be?

Security experts recommend at least 12-16 characters for most accounts. For highly sensitive accounts like banking or email, use 20+ characters. Longer passwords are exponentially harder to crack — a 16-character random password with mixed characters would take centuries to brute-force even with modern hardware.

Should I include symbols in my password?

Yes, when the site allows it. Including symbols significantly increases the number of possible password combinations, making brute-force attacks much slower. However, some websites restrict special characters — in that case, compensate by using a longer password.

What is the difference between a password generator and a passphrase generator?

A password generator creates random strings of characters, while a passphrase generator creates memorable sequences of random words (e.g., "correct-horse-battery-staple"). Both are secure when done properly. Random character passwords are slightly harder to crack per character but harder to remember. Passphrases are easier to type and remember while still being very secure due to their length.