PasswordSecurity.info is a website that helps you create and find good passwords, and suggests modifications you could apply to make them stronger. The site uses the "How Secure Is My Password" open source script and the "Have I Been Pwned" API to check if your password has ever been breached and how long it would take to break it.
This website was originally created to participate in a laptop contest organized by Troy Hunt (@troyhunt).
passwordsecurity.info: https://passwordsecurity.info
Have I Been Pwned: https://haveibeenpwned.com/