How the final exam score you need is worked out
Your course grade is a weighted average: the final exam counts for its weight, and everything you have already done counts for the rest. If the final is worth 25%, your current grade makes up the other 75%.
So the calculator first works out how many percentage points your current grade already brings in, then asks how many more the final has to supply to reach your target, and scales that up by the final’s weight.
Three outcomes are possible. Usually the answer is a score between 0% and 100%. If it is above 100%, the target can’t be reached without extra credit, and the calculator shows the best course grade still possible. If it is 0% or less, you have already secured the grade.
The formula
F = (G − C × (1 − w)) ÷ w
- F
- score you need on the final, in percent
- G
- course grade you want, in percent
- C
- your current grade, in percent
- w
- weight of the final as a decimal (25% → 0.25)
Turned around, it tells you the course grade for any exam score:
G = C × (1 − w) + F × w
Worked example
You have 88% in the course, the final counts for 25% and you want a 90% (an A).
- Your current grade covers 75% of the course: 88 × 0.75 = 66 points.
- You need 90 − 66 = 24 more points from the final.
- The final is worth 0.25, so you need 24 ÷ 0.25 = 96% on it.
For a B (80%) you would need (80 − 66) ÷ 0.25 = 56%, and a C (70%) takes only 16%. A D (60%) is already secured, since even 0% leaves you at 66%. The best course grade you can reach is 66 + 25 = 91%, so a target of 95% would need 116% on the final — not possible without extra credit.
If you score 85% on the final, your course grade is 66 + 85 × 0.25 = 87.25%.
Before you rely on the number
- Check how your grade is weighted. Many courses group work into categories (homework 20%, midterms 30%…). The “current grade” shown in your school’s portal is usually already weighted; use that.
- Other work still to come. If projects or quizzes are still outstanding, your current grade will change, and the score you need will change with it.
- Rounding and curves. Some instructors round 89.5% up to an A, others don’t; a curve changes everything. The syllabus is the authority.
- Letter cut-offs vary. 90/80/70/60 is a common US convention, not a universal rule. Some courses use 93% for an A, or plus/minus bands.
Next step
Once you know your likely course grades, the GPA calculator shows what they do to your grade point average.
Frequently asked questions
What do I need on my final to get an A?
Subtract your current grade times the share of the course the final does not cover from 90, then divide by the final’s weight. With 88% in the course and a final worth 25%, that is (90 − 66) ÷ 0.25 = 96%.
Can I still pass if I fail the final?
Look at the “course grade with 0% on the final” line. If it is at or above the passing mark, you pass even with a zero. The letter-grade table marks every grade you have already secured.
Why does the calculator say I need more than 100%?
Your current grade is too far below the target for the final alone to close the gap. The result shows the highest course grade still reachable. Extra credit, a curve or dropped assignments are the only ways past that limit.
What if my final is worth 100% of the grade?
Then your current grade does not count at all and you simply need the target grade on the final. The calculator accepts weights up to 100%.
Does the calculator work with points instead of percentages?
Convert first: divide the points you have by the points possible so far and multiply by 100 to get a percentage. The percentage calculator can do this in one step.
Last reviewed September 19, 2026