Semester grade calculator
Two quarters and an exam, or any split. Leave one grade blank to solve for it.
Semester exam counts for 20% of the semester.
With 0% on it: 70%. With 100%: 90%.
You need 100% on semester exam for a 90% semester grade.
How a semester grade is figured
Many high schools grade a semester as two quarter grades plus a semester (final) exam, each with a weight. The semester grade is the weighted average:
semester = (Q1 × w1 + Q2 × w2 + exam × w3) / (w1 + w2 + w3)
The calculator divides by the weights’ own total, so 40/40/20 and 2-2-1 give the same answer. Your handbook or syllabus states the split; 40/40/20 and 45/45/10 are only examples, so check yours.
Worked example: 85 and 90 with a 20% exam
Quarter 1 is 85, quarter 2 is 90, and the exam is worth 20%. Before the exam, 80% of the semester is set:
40 × 85 + 40 × 90 = 3,400 + 3,600 = 7,000
For a 90% semester you need (9,000 − 7,000) / 20 = 100 on the exam. For an 80%, (8,000 − 7,000) / 20 = 50. A 0 on the exam leaves 7,000 / 100 = 70%; a perfect exam gives 90%. So the exam can move this student anywhere from 70% to 90%.
Exam score you need, by quarter average
When both quarters carry the same weight, only their average matters: 85 and 90 work the same as 87.5 and 87.5. Find your average on the left and the semester grade you want along the top, in the table for your exam’s weight. “Secured” means even a 0 keeps the grade; “(no)” means you’d need more than 100.
| Quarter average | A (90) | B (80) | C (70) | D (60) |
|---|---|---|---|---|
| 95% | 70% | 20% | secured | secured |
| 92% | 82% | 32% | secured | secured |
| 90% | 90% | 40% | secured | secured |
| 88% | 98% | 48% | secured | secured |
| 85% | 110 (no) | 60% | 10% | secured |
| 82% | 122 (no) | 72% | 22% | secured |
| 80% | 130 (no) | 80% | 30% | secured |
| 78% | 138 (no) | 88% | 38% | secured |
| 75% | 150 (no) | 100% | 50% | secured |
| 72% | 162 (no) | 112 (no) | 62% | 12% |
| 70% | 170 (no) | 120 (no) | 70% | 20% |
| Quarter average | A (90) | B (80) | C (70) | D (60) |
|---|---|---|---|---|
| 95% | 45% | secured | secured | secured |
| 92% | 72% | secured | secured | secured |
| 90% | 90% | secured | secured | secured |
| 88% | 108 (no) | 8% | secured | secured |
| 85% | 135 (no) | 35% | secured | secured |
| 82% | 162 (no) | 62% | secured | secured |
| 80% | 180 (no) | 80% | secured | secured |
| 78% | 198 (no) | 98% | secured | secured |
| 75% | 225 (no) | 125 (no) | 25% | secured |
| 72% | 252 (no) | 152 (no) | 52% | secured |
| 70% | 270 (no) | 170 (no) | 70% | secured |
| Quarter average | A (90) | B (80) | C (70) | D (60) |
|---|---|---|---|---|
| 95% | 75% | 35% | secured | secured |
| 92% | 84% | 44% | 4% | secured |
| 90% | 90% | 50% | 10% | secured |
| 88% | 96% | 56% | 16% | secured |
| 85% | 105 (no) | 65% | 25% | secured |
| 82% | 114 (no) | 74% | 34% | secured |
| 80% | 120 (no) | 80% | 40% | secured |
| 78% | 126 (no) | 86% | 46% | 6% |
| 75% | 135 (no) | 95% | 55% | 15% |
| 72% | 144 (no) | 104 (no) | 64% | 24% |
| 70% | 150 (no) | 110 (no) | 70% | 30% |
The weight changes the answer more than most students expect. At an 82 average, a B needs 72 on a 20% exam, 62 on a 10% exam and 74 on a 25% exam.
How much the exam can move your grade
The heavier the exam, the wider the range. This is a student with an 85 average across the quarters:
| Exam weight | Exam 0 | Exam 70 | Exam 100 |
|---|---|---|---|
| Exam 10% | 76.5% | 83.5% | 86.5% |
| Exam 15% | 72.25% | 82.75% | 87.25% |
| Exam 20% | 68% | 82% | 88% |
| Exam 25% | 63.75% | 81.25% | 88.75% |
| Exam 30% | 59.5% | 80.5% | 89.5% |
At 10% the whole exam is worth 10 points of the semester: the grade can only land between 76.5 and 86.5. At 30% it spans 59.5 to 89.5.
Schools that average letter grades
Some schools average letters instead of percents: each grade becomes points (A = 4, B = 3, C = 2, D = 1, F = 0) and the semester is their weighted average. Quarters of B and A with a C on the exam, weighted 2-2-1, give (2 × 3 + 2 × 4 + 1 × 2) / 5 = 3.2, a B. With an A on the exam it would be 3.6, an A if your school draws the line at 3.5. Switch “Grades as” to letters for this method. Where a school draws the line between letters (3.5 or something else) is set by its handbook, so the calculator shows the exact average too.
More than two grading periods
Schools on six-week or trimester periods use the same math with more rows. The 2-2-2-1 split covers three equal periods and a lighter exam; type your own weights for anything else. For a college course with categories instead of quarters, use the grade calculator, and for one final exam weight against a single current grade, the final grade calculator. To turn semester grades into a GPA, the high school GPA calculator takes it from there.
Semester grade calculator FAQ
How do you calculate a semester grade with a final exam?
Multiply each quarter grade and the exam by their weights, add them, and divide by the total weight. Quarters of 85 and 90 at 40% and an exam of 75 at 20% give (3,400 + 3,600 + 1,500) / 100 = 85%.
What do I need on my semester exam to keep an A?
Subtract your weighted quarter points from 90 × 100 and divide by the exam weight. With quarters of 92 and 94 at 40% each, (9,000 − 7,440) / 20 = 78 on the exam.
What if I get a 0 on the semester exam?
Your semester grade becomes your weighted quarter points divided by 100. With quarters of 85 and 90 at 40/40/20, that is 70%.
Is 2-2-1 the same as 40/40/20?
Yes. Both give each quarter twice the exam’s weight, and the calculator divides by the total either way.
Can I use letter grades instead of percentages?
Yes. Choose letters, and each grade counts as points from A = 4 to F = 0.
Is what I type saved?
No. Everything is computed in your browser and nothing is sent or stored.
How this page was made. Drafted with AI and checked by Silent Student on November 2, 2026. The tables were computed with the same code the calculator runs, using exact fractions. The splits are common examples, not any particular school’s policy. See our editorial policy.
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