Method
A weighted mean is sum(score × weight) ÷ sum(weights). Required final score is (target − current × (1−w))/w, where w is the final exam’s fraction of the course grade.
Worked example
Scores 80, 90 and 100 weighted 20, 30 and 50 give 93%. With a current 85%, a 90% target and a final worth 40%, the required final exam score is 97.5%.
Points and letter grades
Enter scores as points earned out of points possible, such as 45/50, 27/30 and 88/100. Each becomes a percentage (90%, 90%, 88%), then the weights apply: (90 × 20 + 90 × 30 + 88 × 50) ÷ 100 = 89%, a B+ on the common plus/minus bands. Leave the weights blank to grade by total points instead: 160 ÷ 180 = 88.89%.
Letter grades are averaged as grade points. On the 4.0 scale B+ = 3.3, A− = 3.7 and A = 4.0, so weights 20, 30 and 50 give (3.3 × 20 + 3.7 × 30 + 4 × 50) ÷ 100 = 3.77, and the nearest letter is A− (A starts at 3.85, halfway between 3.7 and 4.0). A 4.33 scale option gives A+ its own 4.33.
| Letter | Percent |
|---|---|
| A+ | 97–100 |
| A | 93–96 |
| A− | 90–92 |
| B+ | 87–89 |
| B | 83–86 |
| B− | 80–82 |
| C+ | 77–79 |
| C | 73–76 |
| C− | 70–72 |
| D+ | 67–69 |
| D | 63–66 |
| D− | 60–62 |
| F | below 60 |
Assumptions and limits
The current grade must exclude the final exam. This tool uses a 0–100% score scale; a required score above 100% is not achievable without extra credit. Letter-grade and rounding policies come from your syllabus.