To explain the brute force concept in a few words. It basically is a method to try every possible combination until the right password has been discovered. Passwords that use lots of characters and make use of the complete char set including upper case, lower case, numbers and special chars are harder to brute force.

The Brute Force Calculator lets you enter the amount of chars of the password divided into upper case, lower case, numbers and special characters.

According to the script a single computer can brute force a password consisting of seven lower case chars and one number in 29 minutes while a password consisting of 7 upper case, 7 lower case, 1 number and 1 special char would take 3,129,145,610.89 days to crack on a single machine.

All based on a computer that is able to try 137,438,953,472 combinations per hour. The script is basically interesting for users who are still using short passwords who do not make use of the complete character set possible. It shows them that someone could crack their password in a short amount of time not even taking into consideration using distributed computing to brute force the password.