Is always allowed to take courses as "listener" for free

Hi;

I’m international applicant for graduate study in US.

In know in my home country, as university students you are allowed to register for courses as “listener” without any course fee, provided that the course is not full.

I wonder if it’s same on US in most universities?

Here it is usually called “auditing” a class. You can check with the specific school you are wondering about, but normally you do this with no assessments (grades) or credits.

Yes, there will be no grades … it just matter they allow me to sit on the class.

You have to ask the prof. Some will allow this- especially lectures. Smaller, seminar classes may not due to limited space.

Many universities have a fee for auditing. At the public universities in my state, auditing a course for no credit costs exactly the same amount as taking it for credit.

Honestly at most universities you could just walk into a lecture hall and take a seat. No one would know the difference in those large lectures.

It would really depend on the school, the professor, and the specific class. At some larger US universities, the freshman level introductory classes and general education classes will often have hundreds of students. You could walk into the class, sit down at the back of the lecture hall, and nobody would even notice. It would still obviously be better to have permission to do so.

When you get into upper level classes, the classes often move out of the large lecture halls and into smaller classrooms. These classes often have less than 40 people in them, and sometimes only 10-20. Space in these classes is a lot more limited, so permission to audit the course may also be limited.

This will also depend a lot on the university, the department, and the specific class. At my school (a state university), a lot of upper division classes in large departments were still on the order of 100-200 students (or more, depending on the class). They were popular classes or were required by multiple different majors (or was a class that different majors could take as an elective). Take a look at the class size of anything you want to sit in on. Odds are, if it’s a large lecture-based class, you can just sit in without anyone noticing. If it’s a small class, you will need permission first and may need to pay to officially audit the course.

Yes, it is definitely going to vary quite a bit. Within my own major (physics), the upper level courses tend to be on the smaller side. But very few people aside from physics majors are typically going to take upper level quantum mechanics and such. Some engineers have to and some chemistry/chemical engineering students have to take them, but very few others. Other majors are going to involve upper level classes that can be fairly cross-categorized.