For users already inside a course, the Class ID can often be identified at the end of the browser URL while on the class homepage.

Ask a classmate for the Class ID and password, or email your professor directly. Instructors can resend the enrollment instructions instantly from their class roster page.

Whether you're trying to join a class for the first time or troubleshooting a "Class ID not found" error, this guide breaks down everything you need to know about this essential piece of academic software. What Exactly is a Turnitin Class ID?