Letter grades are based upon total weighted average of all the grade components. The following table shows which letter grades correspond to which ranges of total averages. Sometimes I decide to modify these ranges at the end of the course based upon overall student performance for the semester. I never raise the minimum standard required to earn any grade, however, so if you earn the minimum total average then you are assured of that grade. The table also shows a possible example of modified grade ranges.
Sample Letter Grade Distribution
Grade Standard Point Range Modified Point Range
A 90 - 100% 89.5 - 95%
B 80 - 89.9% 80 - 87.5%
C 70 - 79.9% 69 - 78%
D 60 - 69.9% 58.5 - 66.5%
F 0 - 59.9% 0 - 55%