Grade Calculator · Practical guide
How to Calculate My Grade with Weighted Percentages
Weighted grading rewards the categories that count most — here is the exact formula your instructor uses.
At a glance
The Formula
A weighted course grade is Weighted Grade = (S₁W₁ + S₂W₂ + … ) ÷ (W₁ + W₂ + … ) — multiply each score by its weight, add the products, and divide by the sum of the weights. A plain average only works when every item counts equally, which almost never happens.
Interactive tool
Grade Calculator
Enter your own values, then compare the result with the examples below.
| Assignment | Score (%) | Weight (%) |
|---|
Grade Results
Worked Example
Your syllabus splits the course into four parts, and your scores are in:
| Assignment | Score | Weight | Score × Weight |
|---|---|---|---|
| Homework (average) | 88 | 20% | 1,760 |
| Quizzes (average) | 92 | 20% | 1,840 |
| Midterm | 81 | 25% | 2,025 |
| Final Exam | 85 | 35% | 2,975 |
| Total | 100% | 8,600 |
Divide the products by the total weight: 8,600 ÷ 100 = 86.0% — a B on the standard scale. A plain average of the four scores gives 86.5%, close here only by coincidence; with lopsided weights the two methods can differ by several points.
Weights Do Not Have to Add to 100
The formula self-normalizes, so points work exactly like percentages: a 200-point midterm and a 300-point final behave identically to 40% and 60%. Enter whatever numbers your syllabus uses and the calculator above divides by the total automatically.
Where Students Go Wrong
- Averaging category scores without weights — ignores that the final often counts double the homework.
- Forgetting a category entirely, which silently re-weights everything else.
- Mixing points and percents without converting (the calculator handles this, since it divides by the weight sum).
Frequently Asked Questions
What if my weights add up to more than 100%?
That is fine — the calculator divides by whatever total you enter. Just be aware that extra categories may mean your syllabus uses points, not percentages.
How do I handle dropped quizzes?
Drop the lowest quiz before averaging the quiz category, then enter that category average with its syllabus weight. The calculator treats each row as one category.
Is an 86% a B everywhere?
On the common scale (A ≥ 90, B ≥ 80) yes, and on plus/minus scales 83-86 is a B. Some schools set the B floor at 82 or 84, so check your syllabus.
Can I calculate my grade before the semester ends?
Yes — enter only graded work and the result is your current average over the weight completed. Add a blank-score row for upcoming work to see what you still need.