How to Calculate Your GPA from Scratch

Understanding the 4.0 Scale

GPA (Grade Point Average) is calculated on a 4.0 scale where letter grades convert to grade points: A = 4.0, A− = 3.7, B+ = 3.3, B = 3.0, B− = 2.7, C+ = 2.3, C = 2.0, D = 1.0, F = 0.0.

Semester GPA Formula

GPA = Sum of (Grade Points × Credit Hours) ÷ Total Credit Hours

Example: 3 credits of A (4.0) + 4 credits of B+ (3.3) + 3 credits of B (3.0):

(3 × 4.0) + (4 × 3.3) + (3 × 3.0) = 12 + 13.2 + 9.0 = 34.2
Total credits: 3 + 4 + 3 = 10
GPA = 34.2 ÷ 10 = 3.42

Cumulative GPA

Cumulative GPA averages all semesters weighted by credit hours — not a simple average of semester GPAs. Sum all quality points (grade points × credits) across all semesters, then divide by total credits attempted.

Weighted vs. Unweighted GPA

Unweighted GPA treats all courses equally (max 4.0). Weighted GPA adds bonus points for honors/AP/IB courses (typically +0.5 for honors, +1.0 for AP). Colleges often recalculate GPAs on their own scale — a weighted 4.3 at one school may equal an unweighted 3.8 at another.

Frequently Asked Questions

What is a good GPA?

3.5+ is generally considered excellent (Dean's List level at most schools). 3.0–3.49 is good/above average. Below 3.0 may limit graduate school options. Context matters — a 3.5 in chemical engineering is very different from a 3.5 in a less rigorous program.

Can one bad semester ruin my GPA?

It can significantly impact it, especially in early semesters with fewer credits accumulated. But GPAs can recover — a strong subsequent semester can substantially raise a cumulative GPA. Grade replacement policies (where allowed) can also help.