How it works
Your course grade is a weighted average: the final exam counts for its weight, and everything before it counts for the rest. Solve for the final score that makes the average equal your target.
Needed = (Target − Current × (1 − w)) ÷ w
w is the final's weight as a decimal (25% = 0.25). If the answer is over 100%, the target isn't reachable without extra credit. If it's zero or negative, you've already secured the grade.
Worked example
You have an 85% going into a final worth 25% of the grade, and you want a 90%.
Needed = (90 − 85 × 0.75) ÷ 0.25 = (90 − 63.75) ÷ 0.25 = 105%. A 90 is out of reach, but scoring 100 would give you 88.75%.
With an 88% and a final worth 20%, the same 90% target needs (90 − 70.4) ÷ 0.20 = 98%.
Frequently asked questions
How much is my final exam worth?
Check your syllabus. Finals are commonly 15–30% of the course grade, and some classes use 40% or more.
What if my class uses points instead of percentages?
Turn your points into a percent first (points earned ÷ points possible × 100). The final's weight is its points ÷ total course points.
What letter grade is a 90%?
On the most common US scale, 90–100 is an A, 80–89 a B, 70–79 a C and 60–69 a D, though many schools add plus and minus cutoffs.
What if my current grade already includes some of the final's categories?
Use the grade for everything except the final as "current", and the final's share of the total as the weight. That keeps the math exact.