First digit: year in a sequence

• 1XX = Course for first-year students in the discipline and/or for preps, e.g. PY150Y.

• 2XX = Course for second-year students in the discipline and/or for lower mids.

• 3XX = Course for third-year students in the discipline and/or for upper mids. Introductory-level courses that are open only for upper mids or seniors are also marked at the 300-level. Examples of this might be the upper-class version of Physics (PY350Y) and U.S. History for new upper mids and seniors (HI350Y).

• 4XX = Course for fourth-year students in the discipline and/or for seniors. Departments like H&SS that mainly have one level of course offerings for both upper mids and seniors may mark all upper-level electives at the 400-level.

Additional hundreds designation (for Languages and Math only):

• 5XX = Course for fifth-year students in the discipline

• 6XX = Course for fifth-year students in the discipline

Second digit: honors vs. non-honors

• X0X-X7X = The majority of classes are marked here—there is generally no distinction in the challenge level within this range, though a 0, 1, or 2 may indicate that the course is designed to be more approachable.

• X8X-X9X = Honors-level courses (note one exception is independent studies, which are X99, but not honors courses).

Third digit: course identifier

• No specific meaning. These are now available to expand the number of electives that are possible to keep in the course catalog. 

Letter designation: course timing

• F = Fall

• S = Spring

• P = Portals (Summer)

• Y = Year-long