Calculate a Weighted GPA

statistics

How would I be able to calculate my overall average grade (or grade point average) for these courses?

Course Course Credit (weight) Course Grade
Biology 101 45 86
Psychology 210 30 74
Chemistry 250 45 88
English 200 60 77

My understanding is by simply adding the course grades column together and dividing by the total cumulative possible marks.

(86+74+88+77)/400 = 0.8125

But this number seems very strange in the 0 to 4 GPA.

Best Answer

You calculated an unweighted GPA. To weight it, you must factor in the course credit variable.

> sum=45+30+45+60
> (86*45+74*30+88*45+77*60)/sum
[1] 81.5

As the original units are in a 0-100 scale, your weighted gpa is about a B-.

To convert to a 4.0 scale, simply use the appropriate unit conversion

> 81.5*4/100
[1] 3.26

Your original calculation was missing a multiplication by 4. The procedure for your unweighted gpa should be

> (86+74+88+77)/4*4/100
[1] 3.25
Related Question