The academic calendar is a crucial tool and should be reviewed regularly. Here you will find required information related to both your academic and financial life at the School. The change of program (add/drop) period, holidays and dates by which to submit applications to graduate are just some of the essential information included there. Financial implications are tied to registration and changing your program of study after certain dates. It is important to be aware of how these modifications to your registration are connected to the calendar. Students are responsible for all the information contained within this document. 

http://www.mailman.hs.columbia.edu/studentaffairs/AcademicCalendar.pdf