The score you need on the final for the grade you want
Updated October 2026
Your course grade after the final is a weighted average of two parts: everything before the final, and the final itself. Written out, course grade = current grade × (1 − w) + final score × w, where w is the final's weight as a decimal. Solve that for the final score and you get the formula above. Two numbers fall out of it that are worth knowing before you study: the grade you keep with a zero on the final (current × (1 − w): 59.5% in the 85%/30% example) and the most you can reach with a perfect final (59.5 + 30 = 89.5%).
Each cell is the final exam score needed to finish at exactly 80%. Read across to see how much a heavier final helps a student who is behind and costs a student who is ahead.
| Grade going in | Final 15% | Final 20% | Final 25% | Final 30% | Final 40% |
|---|---|---|---|---|---|
| 95% | 0% (locked in) | 20.0% | 35.0% | 45.0% | 57.5% |
| 90% | 23.3% | 40.0% | 50.0% | 56.7% | 65.0% |
| 85% | 51.7% | 60.0% | 65.0% | 68.3% | 72.5% |
| 80% | 80.0% | 80.0% | 80.0% | 80.0% | 80.0% |
| 75% | 108.3% (out of reach) | 100.0% | 95.0% | 91.7% | 87.5% |
| 70% | 136.7% (out of reach) | 120.0% (out of reach) | 110.0% (out of reach) | 103.3% (out of reach) | 95.0% |
The 80% row is the same in every column: if you are sitting at exactly your target, you need to match it on the final whatever the weight. Below it, a heavier final is your friend; above it, a heavier final is more risk.
If your syllabus gives every assignment points instead of category weights, use the points mode. The calculator adds the final's points to the points possible so far, so a 200-point final in a class with 500 points already graded weighs 28.6% of the course. With 425 of 500 points (85%) and an 80% target, you need 0.80 × 700 − 425 = 135 of the 200 points, which is 67.5%.
The formula assumes the final simply counts for its stated weight. Read your syllabus for rules that change it: a final that replaces your lowest test score, dropped quizzes, a curve, a minimum score required on the final to pass, or a category that is not graded yet (put only graded work into the current grade, or the weight of the missing work makes the result wrong). Letter cut-offs here are the common 10-point scale (90/80/70/60); schools and instructors set their own, so check yours.