A final course grade is a weighted average when the final exam is assigned a fixed part of the course. Convert every percentage weight to a decimal before multiplying.
The formula
Worked example
The coursework average is 86. The final exam is worth 20 percent, so earlier coursework represents 80 percent.
| Component | Score | Weight | Contribution |
|---|---|---|---|
| Coursework | 86 | 0.80 | 68.80 |
| Final exam | 92 | 0.20 | 18.40 |
| Total | 1.00 | 87.20 |
Check what "current average" means
Some gradebooks display an average using only completed work. Others already reserve the final exam as a zero or show category weights that do not yet total 100 percent. Recalculate from the visible category totals when the label is unclear.
Points-based classes
If the course uses total points instead of percentage categories, add earned points and possible points. After the exam, divide total earned points by total possible points. Do not apply a 20 percent exam weight unless the syllabus does.
Run two quick reasonableness checks
The final result should normally fall between the coursework average and the exam score. It should also sit closer to the component with the larger weight. In the example, 87.2 is between 86 and 92 and remains much closer to 86 because coursework supplies 80 percent of the result.
If the answer falls outside that range without extra credit, a weight was probably entered as 20 instead of 0.20, or the current average was counted more than once.
Rounding and letter cutoffs are separate
An 89.95 can become an A-, a B+, or another mark depending on the instructor's rounding and grade-band rules. Keep the numeric estimate separate from the predicted letter.