SGPA=semester grade point average.what you obtained in particular one semester.it is denoted by marks out of 10. YGPA=SGPA/2(of the same year). CGPA=cummulative grade point average or DGPA (1st year YGPA*1+2nd year YGPA*1+3rd year YGPA*1.5+4th year YGPA)/5=CGPA/DGPA. (CGPA/DGPA-.75)*10=Percentage of marks.
I have always wondered, even when I was a student under WBUT (2007-2011), about the deduction of 0.75 from grade point average score! However I have found a link : http://www.wbut.ac.in/announcement/Process_to_Calculate_Percetage_From_Grade_Point.pdf where the table shows that one need to deduct 0.75 from CGPA to get percentage. Can someone clarify? Thanks in advance. :)