How GPA Is Calculated: Weighted vs Unweighted, Explained

GPA (Grade Point Average) compresses an entire semester or academic career into a single number, but the way that number is calculated varies more than most students realize — especially once weighted courses like Honors or AP classes enter the picture.

The basic GPA formula

Standard, unweighted GPA converts each letter grade into a point value, multiplies it by the number of credit hours for that course, sums everything up, and divides by the total credit hours:

On the most common 4.0 scale, letter grades typically map to: A = 4.0, B = 3.0, C = 2.0, D = 1.0, F = 0.0, often with +/- variations adding or subtracting about 0.3 (a B+ might be 3.3, a B- might be 2.7).

A worked example

Suppose you took four courses in a semester: a 4-credit course with an A (4.0), a 3-credit course with a B (3.0), a 3-credit course with an A- (3.7), and a 2-credit course with a C (2.0). The weighted total is (4×4.0) + (3×3.0) + (3×3.7) + (2×2.0) = 16 + 9 + 11.1 + 4 = 40.1, divided by 12 total credits = a GPA of about 3.34. Notice that the 4-credit course influences the final GPA more than the 2-credit one — credit hours act as a weight, not just a headcount.

Weighted vs. unweighted GPA

Unweighted GPA treats every class the same regardless of difficulty — an A in a basic elective counts identically to an A in AP Calculus. Weighted GPA corrects for this by adding extra points for harder courses, commonly:

• Honors courses: +0.5 to the grade point value
• AP or IB courses: +1.0 to the grade point value

Under this system, an A in an AP class might be worth 5.0 instead of 4.0, which is why some students report weighted GPAs above the traditional 4.0 ceiling. There's no single universal standard, though — the exact weighting scale varies by school district, so a 4.6 weighted GPA at one school isn't automatically comparable to a 4.6 at another.

Cumulative GPA vs. semester GPA

Semester GPA only reflects the current term's courses. Cumulative GPA factors in every course taken so far, weighted by credit hours across all semesters. Because cumulative GPA is an average over a growing number of credits, a single bad semester has a smaller effect on cumulative GPA as more semesters accumulate — which is both reassuring for a rough term and a reminder that early grades carry more relative weight.