How this calculator works
Enter your current course grade, the percentage of the final course grade that the final exam counts for, and the grade you want to end up with. The calculator solves for the exam score that would make the weighted average of your current grade and that exam score equal your goal.
The result falls into one of three cases: a normal required score between 0% and 100%, meaning the goal is achievable with that score; a required score above 100%, meaning the goal cannot be reached at this exam weight no matter how well you do; or a required score below 0%, meaning your current grade already guarantees the goal even with a zero on the final. The calculator states plainly which case applies rather than just showing a raw number that might read as achievable when it isn't.
The formula
Course grade = current grade × (1 − weight) + final exam score × weightRequired final exam score = (goal − current grade × (1 − weight)) ÷ weightWeight is entered as a percentage and converted to a decimal (30% becomes 0.30) before use. This is the standard weighted-average setup used whenever a course grade is built from graded components with fixed percentage weights.
Worked example: 80% current grade, final worth 30%, 85% goal
- Convert the weight to a decimal: 30% = 0.30.
- Compute the non-final portion of the goal: 80 × (1 − 0.30) = 80 × 0.70 = 56.
- Subtract from the goal: 85 − 56 = 29.
- Divide by the weight: 29 ÷ 0.30 ≈ 96.67% needed on the final exam.
Frequently asked questions
What does it mean if the required score is over 100%?
It means even a perfect final exam score cannot bring the course grade up to the goal at the given weight — the current grade is too far behind for that exam's weight to make up the difference. The only ways to reach the goal in that case are extra credit, a grade recalculation, or accepting a lower final course grade.
What does it mean if the required score is negative?
It means the goal is already secured: your current grade, combined with the maximum possible weight the final can still shift, guarantees at least the goal grade even with a 0% on the final exam. This commonly happens when the current grade is well above the goal and the final carries a small weight.
Where does the 'current grade' come from if I have several assignments so far?
Compute your current weighted average across everything graded so far, excluding the final exam, and enter that single percentage. If your course weights different assignment categories, that weighted average calculation happens separately from this one.
Does the exam weight need to add up to 100% with everything else?
The exam weight you enter should be exactly the percentage the final counts toward the final course grade, as stated in the syllabus — everything else (all other coursework combined) makes up the remaining 100% − weight, which is exactly what your current grade is assumed to represent.
Can I use this for a final project instead of an exam?
Yes — the formula only cares about the weight of the remaining graded component, whatever form it takes. Enter the project's weight in the course grade in place of an exam weight and the same calculation applies.