Password Strength Checker

How to use

1. Type a password in the field.
2. The strength meter updates as you type.
3. The entropy in bits tells you how hard the password is to brute-force.

About this tool

Password strength is a function of length and character variety. A 6-character password using only lowercase letters has about 28 bits of entropy — a modern GPU cracks it in seconds. A 16-character password mixing uppercase, lowercase, digits and symbols has about 105 bits — beyond brute-force reach.

This checker scores the password on five levels based on length, the character sets used, and the resulting entropy. It does not check against leaked password databases or dictionary attacks — for that, use the "senha-vazada" tool.

The entropy is calculated as length × log₂(pool size), where the pool is the number of possible characters. It is a theoretical measure — in practice, a password like "Password1!" has high entropy by formula but is trivially guessable because it follows a common pattern.

The formula

Entropy = length × log₂(character pool size). Pool: lowercase 26, uppercase +26, digits +10, symbols +32.

Frequently asked questions