Semester Grade Calculator
Combine your two quarter (or grading-period) percentages and the final exam into one semester grade. Pick the weighting your school uses — 40/40/20 is the most common — and get the average, a letter grade, and the point breakdown.
Example: with Quarter 1 grade (%) 88 · Quarter 2 grade (%) 92 · Final exam grade (%) 85 · Weighting 40% + 40% + 20% exam (most common) → Semester grade: 89.0%.
- Letter gradeB+ (typical US 10-point scale with plus/minus — your school may differ)
- Where the points come fromQ1 35.2 + Q2 36.8 + final 17.0 = 89.0 points
Computed by the calculator below using its default values. Change any input to see your own numbers.
Semester grade = Q1×w1 + Q2×w2 + Exam×w3. The classic US high-school weighting is 40% + 40% + 20%.
How the 40/40/20 split works
Most US high schools compute a semester grade from the two quarter grades and a semester exam, weighted 40% + 40% + 20%. Each quarter point is worth 0.4 semester points and each exam point 0.2 — so the exam can move your semester grade by at most 20 points, and in practice a great-versus-poor exam (say 100 vs 70) swings the result by 6 points, often a full letter.
Schools vary: some weight 45/45/10, some skip the exam, and some average three terms evenly. The dropdown covers the common schemes; check your syllabus or student handbook for the one that binds.
Planning backward from the grade you want
Run the math in reverse before exam week. With quarters of 88 and 92 under 40/40/20, you carry 72 points in, so an A at 90 requires (90 − 72) ÷ 0.2 = a 90 on the final. That backward calculation — target minus banked points, divided by the exam weight — is the single most useful thing this formula does.
How it’s calculated
Semester grade = Q1 × w1 + Q2 × w2 + Final exam × w3, with weight sets 40/40/20, 45/45/10, 50/50 (no exam), or equal thirds. Letter grades use the typical US 10-point scale with plus/minus (A ≥ 93, A− 90–92.9, B+ 87–89.9, and so on down to F below 60).
Your school controls the weights, rounding, and letter cutoffs — semester policies vary by district and even by department, so treat this as the standard-convention version.
Same grades, different weightings (Q1 = 88, Q2 = 92, exam = 85)
| Weighting | Semester grade | Letter |
|---|---|---|
| 40 / 40 / 20 | 89.0% | B+ |
| 45 / 45 / 10 | 89.5% | B+ |
| 50 / 50 (no exam) | 90.0% | A- |
| Equal thirds | 88.3% | B+ |
Computed with this page's formula; 40/40/20 is the most common US high-school semester weighting.
Common mistakes
- Averaging the quarters and exam equally when your school uses 40/40/20 — that hands the exam 33% weight instead of 20%.
- Entering letter grades as guessed points — a B+ is not 89 everywhere; use the actual percentages from the gradebook.
- Folding the exam into Quarter 2 — at most schools it is a separate grade with its own weight.
- Rounding each component before combining; schools typically round only the final semester average.
Frequently asked questions
How is a semester grade calculated?
Semester grade = Q1 × w1 + Q2 × w2 + exam × w3. With the common 40/40/20 weighting and grades of 88, 92, and 85, that is 35.2 + 36.8 + 17.0 = 89.0%.
What do I need on the final to get an A?
Subtract your banked quarter points from the target, then divide by the exam weight. Quarters of 88 and 92 bank 72 points under 40/40/20, so a 90 target needs (90 − 72) ÷ 0.2 = 90 on the exam.
What if my class has no final exam?
Use the 50/50 option — the semester grade is simply the average of the two quarters. Some schools weight the second term slightly heavier; check your handbook.
Does an 89.5 round up to 90?
That is pure school policy. Many gradebooks round half up, some truncate, and some leave the decision to the teacher — the calculator shows the unrounded value so you can see exactly where you stand.
How does the semester grade affect GPA?
At most US high schools the semester letter grade is what posts to the transcript and feeds GPA — quarters are progress reports. That makes the semester calculation the one that counts.