Password strength checker
Type a password and see its entropy in bits and the estimated time to crack. Everything runs in the browser: the password is never sent anywhere and never stored.
The estimate assumes pure brute force. A password built on a dictionary word, a name or a date falls far faster whatever entropy the calculation shows, because attackers try leaked password lists first.
Frequently asked questions
Does my password really stay local?
Yes. The whole calculation runs in JavaScript in your browser, this page makes no network call, and nothing is stored. You can verify it by going offline before testing.
What makes a password genuinely good?
Length, ahead of complexity. A four-word random passphrase is harder to crack than eight characters with symbols, and far easier to remember.
Why use a password manager?
Because the real problem is not the strength of one password but reuse. A breach at some minor site becomes access to your email if the password is the same.
Does two-factor still matter with a strong password?
Yes, and it matters more than the password. It stops phishing and credential stuffing, which no password defends against.