Weighted Average Calculator
The formula
In a weighted average, each value counts according to its weight (coefficient, credits or importance):
Weighted average = Σ(value × weight) ÷ Σ(weights)
Enter the grades in the first field and the weights in the second, in the same order and separated by commas.
Worked example: grades with coefficients
Grades out of 20 of 14 (coefficient 3), 12 (coefficient 2) and 16 (coefficient 1):
- Weighted sum: 14 × 3 + 12 × 2 + 16 × 1 = 42 + 24 + 16 = 82
- Sum of coefficients: 3 + 2 + 1 = 6
- Weighted average: 82 ÷ 6 = 13.67
The simple average of the same grades would be 14: the low grade in a high-coefficient subject pulls the result down.
Worked example: US GPA
On the usual 4-point scale, A = 4, B = 3, C = 2, D = 1, F = 0, weighted by course credits:
| Course | Grade | Points | Credits |
|---|---|---|---|
| Biology | A | 4 | 3 |
| Calculus | B | 3 | 4 |
| History | C | 2 | 2 |
Enter grades "4, 3, 2" and weights "3, 4, 2": (12 + 12 + 4) ÷ 9 = GPA 3.11. Some schools use plus/minus grades (A− = 3.7, B+ = 3.3) — check your institution's scale.
Other uses
- Average purchase price: buying 10 shares at €50 and 30 at €40 gives an average cost of (500 + 1,200) ÷ 40 = €42.50, not €45.
- Survey or index scores: criteria of different importance.
- Average speed over legs of different durations.
What grade do I need?
To reach a target average, solve for the missing grade: needed = (target × total weights − current weighted sum) ÷ weight of the remaining exam. To reach 14 with the example above plus an exam of coefficient 2: (14 × 8 − 82) ÷ 2 = 15.
Frequently Asked Questions
What is the difference between an average and a weighted average?
A simple average treats every value equally. A weighted average multiplies each value by its importance (coefficient or credits) before dividing by the total weight.
How do I calculate my GPA?
Convert each letter grade into points (A = 4, B = 3, C = 2, D = 1, F = 0), enter them as grades and the course credits as weights.
Do the weights have to add up to 100?
No. The calculator divides by the sum of the weights, whatever it is. Percentages or coefficients both work.