Password Cat is a free web app to test your passwords' strength and let you generate new ones. It makes use of advanced algorithms to evaluate your password and give it an easy to understand grade. It also compares your password with a list of the most common used ones so you don't use a super easy to break dictionary password.
The app is available in english, portuguese and spanish. Other languages may be available soon.
To make it even more secure, all action happens in the browser. In this way no password is sent to the server and you, the user, can rest assured the passwords you test remain yours and yours only.
Check it out at https://passwordcat.top