Password Checker

Check how strong a password is, what makes it weak, and whether it has appeared in a known data breach.

Runs in your browser. Files are not uploaded.

How to use

  1. Type a password.
  2. Read the strength and suggestions.
  3. Optionally check it against known breaches.

Questions

Is my password sent anywhere?

No. The strength check runs in your browser. The breach check sends only the first 5 characters of the password’s SHA-1 hash to Have I Been Pwned, and compares the results on your device, so the password itself never leaves it.

How is the crack time worked out?

It assumes an attacker with a copy of a leaked password database, trying about 10 billion guesses a second. Common passwords and patterns are guessed first, so they count as much weaker.

What makes a strong password?

Length and randomness. A password manager’s random password, or four or more random words, is best.

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