How do I calculate my GPA?

http://reslife.berkeley.edu/gpa-calculator

GPA is generally on a 4-point scale.

How percentage grades match to grades and grade points is not necessarily the same between schools. You should probably ask your school. Of course, not all schools even relate to GPA’s.

However, often the scale is something like:
90–100 A
80–89 B
70–79 C
60–69 D

So one might read your grades as A, A-, D+, A-, B+, A

Plugging those into the link @johnpowell provided, and assuming all classes have the same weight, I get a GPA of 3.333. (i.e. a B+ average)

I did a Web search for this and found this site. Using their chart to convert percentages to GPA and taking the average, I get 3.28, which would be a B.

Do what @johnpowell suggested (the answer would be a B for final) but don’t you have access to something where you can get a transcript? to see your GPA? My school does but I don’t know if all schools have that readily available. Especially if you aren’t in American school systems.