A strong password is an important security feature and we want to help you create a strong deterrent.
How do we determine the strength of a password? We test the strength of a password by calculating how long it would take to crack with brute force.
Unlike most password strength checkers that just require one of each lowercase/uppercase/number/special characters/at least 6 characters/etc, Circle's more holistic approach provides you with an actionable recommendation to make your password more secure. We require two-factor authentication when you sign in, so even if your password is compromised you have a second layer of security. (What is two-factor authentication?)
Remember, it is your responsibility to have a strong password -- but it is also your responsibility to remember that password! Please make a point to remember or securely store your information.