For example – you have 6 classes at 3 credits each (I don’t remember high school exactly, so you’ll have to check how many credits each class is). So say you got 3 B’s and 3 A’s to average your 90.64. So you have 3 classes at 3 credits each, so 9 total credits. You multiply those 9 credits times 3 for a B, and you have 27 GPA points. Then, you take your 3 A classes, do the same process, 3 x 3 x 4 = 36. Add those together and you have 63 GPA points. Then divide by your total credits – 6 x 3 = 18. 63/18 = 3.5 on your 4 point GPA scale.

If you don’t have credits per class, you can assume each class is one credit, which simplifies things. 6 classes, 3 points per B, 4 points per A. 3 + 3 + 3 + 4 + 4 + 4 = 21. 21 divided by 6 classes = 3.5