FocusFlow LabThe formula
You need three numbers: your current grade, the weight of the final (as a percentage of the course) and the grade you want. Then:
Needed score = (target − current × (1 − weight)) ÷ weight
Use decimals for the percentages: a 30% final has a weight of 0.30. The current grade must be the grade on everything before the final.
The final grade calculator does this in one step. If your course has several weighted categories, work out the current grade with the weighted grade calculator first.
Example 1: a score you can reach
You have 78% going into a final worth 40%, and you want an 80% overall.
(80 − 78 × 0.60) ÷ 0.40 = (80 − 46.8) ÷ 0.40 = 83% on the final.
Example 2: a score that cannot be reached
You have 85% going into a final worth 30%, and you want a 90% overall.
(90 − 85 × 0.70) ÷ 0.30 = (90 − 59.5) ÷ 0.30 = 101.7%.
Anything over 100% means that grade is out of reach unless the course offers extra credit. Check the next grade down: for an 88% overall the same sum gives 95%.
What to do with the number
- Under 60%: comfortable. Review the basics and keep the exam low stress.
- 60 to 85%: a normal study plan. Give the exam the hours you would give any final.
- Over 90%: it will take your best work. Put this exam first in your schedule, and check with your teacher whether rounding or extra credit applies.
With several finals, share your time by this number: the exam that needs the highest score gets the most hours. The multiple exams guide shows the split.
Check your syllabus
Some courses drop the lowest score, scale grades or round up. This formula assumes none of that, so treat the answer as a close estimate and confirm with your instructor.
Source: Weighted-average grade formula. Check your syllabus for the weights and any drop, scaling or rounding rules.