Password Strength Checker

What is a Password Strength Checker?

A Password Strength Checker evaluates how resistant your password is to attack using an estimated entropy score. Length, character diversity and similarity to common passwords are checked, with the result shown from very weak to very strong and each missing requirement flagged.

What is entropy and why does it matter?

Entropy measures a password's unpredictability in bits. Every extra character and new character type multiplies the combinations a brute-force attack must try. An 8-character lower-case-only password is weak; the same length with digits and symbols is far stronger. This tool uses the same measure as our password generator.

Is my data safe?

Yes. The test runs entirely in your browser; your password is never sent, stored or logged. Test even your real passwords with confidence.

FAQ

• What length is enough? Aim for at least 12 characters; 16+ is safer.
• Do you check the common-password list online? No — the list is embedded on your device.
• What is the best password? A unique, long, unpredictable password stored in a password manager.