Password Strength Checker

Estimate entropy and crack time of a password

Use this when you need a fast, accurate result — no sign-up, works entirely in your browser.

Password to check

Strength—

Entropy (bits)—

Estimated crack time—

How to Use

Enter your details into the fields above.
Click the calculate button to get your result instantly.
Use the clear button to start a new calculation.

Example

MyP@ssw0rd! → Strong · ~72.3 bits entropy · estimated crack time: years
C0rrect-Horse-Battery → Very strong: entropy ≈ 137.97 bits (crack time centuries+)

Formula

Entropy (bits) = length × log₂(charset size). Charset size = 26 (lowercase) + 26 (uppercase) + 10 (digits) + 33 (symbols), depending on which sets the password uses.

About Password Strength Checker

Estimate entropy and crack time of a password. This free online tool gives you fast, accurate results without registration or downloads.

Everything runs locally in your browser, so your data is never uploaded or stored — privacy first.

Frequently Asked Questions

Is this tool free to use? +

Yes, it is completely free with no registration or download required.

Is my data private? +

Yes. Everything is processed locally in your browser. Nothing is uploaded or stored on our servers.

Does it work on mobile? +

Yes, it works on any device — phone, tablet, or desktop.