Password Strength Checker

What is the Password Strength Checker?

This tool estimates how strong a password is by measuring its entropy — the effective character set it draws from raised to the power of its length — and checks it against a short list of practical criteria: length, character variety, and whether it matches one of the most commonly leaked passwords found in real-world data breaches.

How to use it

1. Type a password into the box (click "Show" to reveal it while checking).
2. Review the estimated strength, entropy, and which checklist items pass.

An honest note on what this can and can't tell you

Entropy is a useful, well-established way to compare passwords, but it's still an estimate: it assumes an attacker has to guess characters somewhat randomly from the character types you used, and it can't know whether your password is a well-known phrase, a keyboard pattern, or your pet's name spelled backwards — patterns that a real attacker's dictionary-based cracking tool would try first, long before brute-forcing every possible combination. Treat a "Weak" or "Moderate" result as a real signal to change the password, but don't treat a high entropy score alone as a guarantee of safety if the password is still a predictable phrase. As with every tool on this site, nothing you type here is sent anywhere — the check runs entirely in your browser.