無料オンラインパスワード強度チェッカー

Length is the biggest factor — each additional character multiplies combinations exponentially. Mix character types (uppercase, lowercase, numbers, symbols). Avoid dictionary words, names, dates, and keyboard patterns (qwerty, 1234).

Absolutely not. All strength analysis runs entirely in your browser using JavaScript. Your password never leaves your device or browser tab.

Minimum 12 characters for important accounts; 16+ is better. A random 16-character password takes billions of years to brute-force even with modern GPU attacks. A passphrase of 4+ random words is easier to remember and equally strong.

The estimate uses zxcvbn (Dropbox's password strength library) combined with known attack speeds: online throttled attacks (~100/hour), offline dictionary attacks (~10 billion/second), offline GPU brute force (~100 billion/second).

Yes, highly recommended. Password managers (Bitwarden, 1Password, Dashlane) generate and store unique strong passwords per site. You only remember one master password. This eliminates password reuse — the biggest security risk.

Yes, the パスワード強度チェッカー on Allio Tools is completely free with no sign-up or registration required. It works directly in your browser.

パスワードの強度を確認し、改善提案を受けます。 No data is sent to a server — everything runs locally in your browser for maximum privacy and speed.

No installation needed. The パスワード強度チェッカー runs entirely in your web browser on any device — desktop, tablet, or mobile.

Completely safe. The パスワード強度チェッカー processes everything locally in your browser. No input data, results, or usage information is ever transmitted to or stored on any server.

After the page loads for the first time, the パスワード強度チェッカー works without an internet connection for all client-side processing. Tools that fetch live external data (such as DNS or network lookups) require an active connection.

The パスワード強度チェッカー fetches live data in real time each time you run it. Results reflect the current state of the server or domain at the moment of the request.

Results depend on the real-time state of the target server and DNS propagation, which can vary by geographic region and caching TTL. If you see inconsistencies, wait a few minutes and re-test — DNS changes can take up to 48 hours to propagate fully worldwide.

Yes. The パスワード強度チェッカー is built with standard browser APIs and works on all modern browsers including Chrome, Firefox, Safari, and Edge — on both desktop and mobile. No plugins, extensions, or third-party software are required.

Select and copy the result text to paste into any document or app. For image tools, a Download button saves the file directly to your device. Your browser's built-in screenshot function also captures results quickly. No account or login is required.