How we calculated grades Grading Rubric Number of Points Letter Grade Greater than or Equal to: But Less than: 105 164 A+ 95 105 A 87 95 A- 79 87 B+ 71 79 B 63 71 B- 55 63 C+ 47 55 C 39 47 C- 31 39 D+ 23 31 D 15 23 D- 0 15 F