Password Strength Checker
Entropy & crack-time estimate.
Runs entirely in your browser — nothing you enter is uploaded, logged, or tracked.
Type a password to see an estimate of its strength — based on length and character variety (entropy), with penalties for common patterns — plus a rough crack-time at modern guessing speeds. Crucially the password stays in your browser: it is never transmitted, stored or logged, unlike sites that “check” your password on a server.
🔒 Checked entirely on this page — your password makes no network request and is never stored.
Frequently asked questions
Is my password sent anywhere?
No — never. The check runs entirely in your browser with no network request. That is the whole point: a password you paste into a server-side checker is a password you have shared.
How is strength estimated?
From entropy (length × the size of the character set used) with penalties for common patterns like dictionary words, repeats and sequences. It is an estimate, not a guarantee.
What makes a strong password?
Length beats complexity — a long passphrase of several random words is both strong and memorable. Aim for high entropy and avoid anything guessable about you.