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How to Calculate a Weighted Grade Average
Updated 2026-04-29
Your course grade is rarely a simple average of every score you've earned. Most classes weight different assignment categories differently — homework might count for 20%, midterms for 30%, and the final exam for 50%. A weighted grade reflects that reality.
The Formula
Weighted Average = Σ(score × weight) ÷ Σ(weight)
Multiply each category's score by its weight, sum those products, then divide by the total weight used. If your weights add up to 100%, the denominator is 100.
Step-by-Step Example
Say your syllabus breaks down like this:
| Category | Your score | Weight |
|---|---|---|
| Homework | 88% | 20% |
| Quizzes | 75% | 15% |
| Midterm | 82% | 25% |
| Final exam | 91% | 40% |
Calculation:
(88 × 20) + (75 × 15) + (82 × 25) + (91 × 40)
= 1760 + 1125 + 2050 + 3640
= 8575
8575 ÷ 100 = 85.75%
Your weighted course grade is 85.75% — a solid B.
Mid-Semester Calculation
If the final exam hasn't happened yet, just leave it out. Divide by the weight of the categories you have:
(88 × 20) + (75 × 15) + (82 × 25)
= 1760 + 1125 + 2050 = 4935
4935 ÷ 60 = 82.25%
This tells you your current standing based on completed work.
Common Mistakes
- Using a simple average: Adding all scores and dividing by the number of categories ignores the different weights.
- Weights that don't add to 100%: Double-check your syllabus — some professors have late additions or drop scores that change the weights.
- Confusing a category average with individual scores: Calculate your average within each category first, then use that single number for the weighted calculation.
Quick Tool
Use the Weighted Grade Calculator to enter your scores and weights without doing the arithmetic by hand.