GPA Calculation Explained: Semesters, Cumulative, and Weighted
From 4.0 scale to weighted honors—everything you need to know
Understand how GPA is calculated from scratch. Covers unweighted 4.0 scale, weighted AP/IB scales, cumulative GPA combining semesters, and the target GPA math.
What You'll Learn
- •Letter grade to grade point mapping
- •Credit hour-weighted GPA formula
- •Unweighted 4.0 scale explained
- •Weighted AP/IB/Honors GPA calculation
- •Cumulative GPA across multiple semesters
- •Target GPA solver formula
- •BCPM (science) GPA for pre-med
- •What-if grade analysis
Full Guide
Grade Point Average (GPA) is the cornerstone of academic evaluation worldwide. But the math behind it—weighted credits, cumulative totals, and target GPA solving—confuses many students and parents.
The Fundamental Formula
GPA = Σ(grade points × credit hours) ÷ Σ(credit hours). Each letter grade maps to grade points: A=4.0, A-=3.7, B+=3.3, B=3.0, B-=2.7, C+=2.3, C=2.0, C-=1.7, D+=1.3, D=1.0, F=0.0.
Weighted GPA for Honors, AP, and IB
Weighted GPA adds grade point bonuses:
- Honors: +0.5
- AP/IB/Dual Enrollment: +1.0
So an A in AP Chemistry = 5.0 (not 4.0). Some high schools use 5.0 as the maximum; others cap at 4.0 for class rank but still show weighted GPA.
Cumulative GPA Across Multiple Semesters
Sum all grade points from every term, divide by total credit hours attempted.
Example:
- Semester 1: 12 credits × 3.5 GPA = 42 quality points
- Semester 2: 15 credits × 3.8 GPA = 57 quality points
- Cumulative: (42 + 57) ÷ (12 + 15) = 99 ÷ 27 = 3.67
Target GPA Solver
Calculate required GPA in future semesters: Required = (desired cumulative points - current points) ÷ remaining credits.
Example: You have 45 credits with 3.2 GPA (144 quality points) and need 3.5 cumulative with 15 more credits:
- Required = (3.5 × 60 - 144) ÷ 15 = (210 - 144) ÷ 15 = 66 ÷ 15 = 4.4 — which is impossible. You'd need a 3.8 to reach 3.4 cumulative.
Special Cases
Pre-med students track both overall GPA and BCPM GPA (Biology, Chemistry, Physics, Math) separately for medical school applications.