Understanding the Course Catalog

Confused by the different numbers and letters you’ll find at the end of a course name? Not sure how you can tell whether a class is a lecture, seminar, or activity course? Your Academic Advisors are here with the answers!

What Do the Course Numbers Mean?

Stanford does not have a standardized course numbering system. This means that each department is free to number its courses in its own way. One common (though not universal) numbering guideline you will see across many departments is as follows:

1-99: introductory level courses for all students
100-199: courses primarily for undergraduate majors and minors
200-299: courses for advanced undergraduates and beginning graduate students
300 and above: courses for graduate students

Again, this numbering is not a universal rule. And even when departments do follow these numbering guidelines, they are not necessarily set in stone. For example, you can often take a 100-level course intended for majors even if it's outside of your field, though you should expect it to be a bit more advanced than an introductory course.

If you're unsure if a course is the right level for you, start off by reading its description carefully in ExploreCourses. If you're still not certain, we recommend you check in with the course instructor, the department's Student Services Officer, or your Academic Advisor.

What Do the Letters After Course Numbers Mean?

You've likely noticed that many courses end with a letter. Maybe you have heard of (or taken) CS106A or English 9CE. But what do those letters mean? The short answer is that it varies. Different departments use these letter to signify different things.

There are a few standard guidelines that you will see across many departments:

N: frosh IntroSem course
Q: sophomore IntroSem course
SC: Sophomore College program course
AX: Arts Intensive program course
SI: Student-Initiated course

The use of other letters depends on the department. Be sure to read the full course description in ExploreCourses for guidance, and click the blue Schedule link to see if there is more information in the Notes. Here are some common approaches (note that "A" is used differently in each one):

  • Letters frequently signal that courses are a variation on the same basic content, such as with Engr40, Engr40A, Engr40M; HumBio120 or HumBio120A; Math61CM or Math61DM.
  • "A-B-C" will sometimes refer to a sequence of courses, but not always--you can usually tell from the course descriptions and prerequisites.
  • "A" may also be used to denote a 1-unit auxiliary course or a course with an additional auxiliary component, such as CS103A or Math51A, although there are many different ways auxiliary courses are presented.
  • An "A" in a PWR course might even stand in for the instructor's initials.

See if the courses in your department show a pattern, or consult the department SSO, your Academic Advisor, or your Major Advisor.

How do I know if a class is a lecture, seminar, activity, or practicum?

All courses have a 3-letter component code listed in the course catalog. This component code tells you what kind of class the course is intended to be. You can find this component code by looking up the course on ExploreCourses and clicking on the blue Schedule link. Here are some common examples:

LEC: lecture courses
DIS: discussion section component of a lecture course
SEM: seminar courses
PRC: practicum courses
COL: colloquium courses
ACT: activity courses

Lecture courses are often larger courses focused on (not surprisingly) the instructor giving a lecture. Discussion sections are often smaller groups where students can talk about and practice the concepts taught in lecture. Seminar courses are usually smaller classes with an emphasis on classroom discussion. Practicum courses usually focus on practice and the application of your skills: music lesson courses for voice, piano, guitar, etc. are all practicums, for example. Colloquium courses often have rotating guest speakers each week to talk about different topics.

Activity courses are a special category worth paying attention to, for reasons explained below.


Which classes are activity units?

All courses with the component code ACT are activity classes, sometimes called "activity units" or ACT units. All Student-Initiated courses (with SI after the course number, eg Anthro 13SI) are ACT units. Athletic and Physical Education courses are generally activity units. Activity units are always only graded Satisfactory/No Credit.

Many activity courses are offered for 1 or 2 units, making them easy to fit into your schedule. But not all all small unit courses are activity units. Check the component code on ExploreCourses! Course marked SEM (seminar), PRC (practicum), WKS (workshop), and so forth are NOT activity units. Wellness and Outdoor courses are usually activity units, but not always. Most music and dance practice courses are NOT activity units (one exception being Dance 46: Social Dance, which is an activity unit).

When do activity units matter?

Only 8 completed activity units may count toward the 180 total units needed for graduation. The detailed version of your Unofficial Transcript has an addendum at the bottom showing how many activity units you’ve attempted and earned, so you can check your total there.

However, that doesn't mean you can only ever take 8 activity units. You can take as many activity units as you like -- just be aware that only 8 of them will count in your total units towards graduation.

No matter how many you've taken and completed in the past, activity units will always count toward the 12 units required to be a full-time student. Even if you've taken more than 8 activity units total, you might still take more activity units in future quarters to qualify as a full-time student, even with the awareness that any activity units beyond the first 8 will not count toward your graduation total.