Weighted average (a) is equal to the sum of the product of the weight (wi) times the data number (gi) divided by the number of subjects. It is a mean calculated by giving values in a data set more influence according to some attribute of the data. Here is a simple free online Grade Calculator which helps you to calculate the average grade. The weighted average simply takes into account how much each course is worth when calculating the average.
By using weighted average, grades are computed. You can simply add up all the item values and divide by the total number of subjects to calculate the average.
A student has earned marks in Physics & Maths as follows:
Physics 89% (Weight - 9)
Maths = 75% (Weight - 7)
Average Grade = ∑ ( 89 x 9) + (75 x 7) / 2
= ∑ (801 + 525) / 2