Weighted Average Calculator
A weighted average gives more importance to grades with higher weight. It works for courses with different credits, assessments with different percentages, or projects that are not worth the same.
With grades of 85 (weight 3), 92 (weight 4), and 78 (weight 2), the weighted average is 86.56. The weight-4 grade (92) influences the result more than the others.
Formula
Average = Σ(grade × weight) ÷ Σ(weights)
Step-by-step example
- Grade 1 = 85 with weight 3 → 85 × 3 = 255
- Grade 2 = 92 with weight 4 → 92 × 4 = 368
- Grade 3 = 78 with weight 2 → 78 × 2 = 156
- Sum of products = 255 + 368 + 156 = 779
- Sum of weights = 3 + 4 + 2 = 9 → 779 ÷ 9 = 86.56
Scenario table
| Grades | Weights | Weighted average |
|---|---|---|
| 85, 92, 78 | 3, 4, 2 | 86.56 |
| 70, 80, 90 | 1, 1, 1 | 80.00 (simple average) |
| 60, 100 | 5, 5 | 80.00 |
| 50, 90 | 2, 8 | 82.00 |
Worked example with college credits
Imagine a semester with three courses: one of 5 credits (grade 70), one of 3 credits (grade 85), and one of 2 credits (grade 90):
- Sum of products = 70×5 + 85×3 + 90×2 = 350 + 255 + 180 = 785
- Sum of weights = 5 + 3 + 2 = 10
- Weighted average = 785 ÷ 10 = 78.50
The simple average would be (70+85+90) ÷ 3 = 81.67. The 5-credit course drags the result down because it is worth more — exactly what the weighted average is designed to reflect.
How to interpret the result
You can use credits, percentages, or units as weights: they do not need to add up to 100, because the calculator divides by the total weight. If all weights are equal, the weighted average matches the simple average. This calculation is the standard in universities for GPA and averages across courses with different values.
The calculator uses the standard formula Σ(grade×weight)/Σ(weights). Check how your institution weights (credits, hours, percentages) so the weights you enter are correct. Some schools round or use different scales (0-4, 0-100, letters), so confirm the criteria of your institution.
Common mistakes
- Using the simple average when courses have different credits.
- Entering weights in the wrong field (grade where the weight goes and vice versa).
- Assuming weights must add up to 100 when working with credits.
- Including empty or pending rows: rows with zero weight are ignored, so they do not distort the result.
Frequently asked questions
Multiply each grade by its weight, add the products, and divide by the sum of weights. Example: (85×3 + 92×4 + 78×2) ÷ 9 = 86.56.
No. The formula divides by the total weight, so it works with credits, units, or percentages regardless of the sum.
No, they are ignored. That way you can leave empty or pending rows without affecting the result.
Only if the weights differ. With equal weights, both match: (70+80+90)÷3 = 80 with weights 1,1,1.
Yes. A weighted average also works for performance scores with different weights, academic credit averages, or any set of values with different importance.
Related calculators
- Final grade needed: what you need for your target
- Study hours: plan your studying
- Percentages: convert weights and percentages
- Rule of three: grade and credit proportions