How to calculate GPA

A student’s grade point average (GPA) can have an impact on money for college. Grandparents might reward good grades with contributions to the grandchild’s 529 college savings plan. Eligibility for private scholarships might be based on the student’s GPA. Great grades and test scores can affect a student’s admissions chances at the most selective colleges and universities.

Thus, it is important to know how to calculate a student’s GPA.

As the name grade point average suggests, the GPA is an average of the student’s grades. There are two types of averages, weighted and unweighted.

How to calculate an unweighted GPA

The unweighted GPA is a simple average of the points assigned to each grade. 

Letter grades are translated to grade points on a 4.0 scale, with an A equal to a 4.0, as shown in this table.

Pluses and minuses add and subtract 0.3 grade points. Thus, a B+ is 3.3 grade points and an A- is 3.7 grade points.

Decimal grades on a 100 point scale can be converted to a 4.0 scale by subtracting 55 and dividing the result by 10, possibly capping the result at 4.0.  

Some schools differ in how they handle an A+. Some schools will add 0.3 grade points to the 4.0 for an A, yielding 4.3 grade points on a 4.0 scale for an A+. Others consider an A to be the highest possible grade, and therefore treat an A+ as having 4.0 grade points, the same as an A.

To calculate the unweighted GPA, sum the grade points for each class and divide the sum by the number of classes. For example, if you took three classes with a C+, B and A, the sum of the grade points would be 2.3 + 3.0 + 4.0 = 9.3. Dividing this by 3 classes yields a GPA of 3.1.

How to calculate a weighted GPA 

Some schools take this a step further and assign a different number of credits to each class. Some classes are worth more credits than others. The weighted GPA multiplies the number of credits for each class by the grade points earned and divides the sum by the total number of credits.

Suppose you earned the same grades as before, a C+, B and A, but the classes were worth 2, 3 and 4 credits, respectively. The weighted sum of the grade points would be 2.3 x 2 + 3.0 x 3 + 4.0 x 4 = 29.6. Dividing this weighted sum by the total number of credits, 9, yields a weighted GPA of 3.29.

Using bonus points to boost the GPA

The weighted GPA will still be 4.0 or less on a 4.0 scale. So, how do some students end up with a weighted GPA greater than 4.0 on a 4.0 scale?

If the school treats an A+ as earning 4.3 grade points, that can lead to a GPA that is greater than 4.0. 

Some schools add bonus grade points to reflect the greater difficulty of more challenging classes, such as Honors, AP and IB classes. Typically, schools will add a half point (0.5) for honors classes and a full point (1.0) for AP and IB classes.

How colleges calculate high school GPA

Since every high school calculates GPA differently, colleges ignore the GPA submitted by the guidance counselor. Instead, they calculate their own GPA from the student’s academic transcripts. 

Colleges start with the core classes that are required for admission. The core classes include English, Social Studies, History, Science, Mathematics and Foreign Languages. Your 4.0 in Physics counts, but not a 4.0 in Physical Education.

They then calculate a simple GPA of the core classes, without any bonus points for Honors, AP and IB classes. 

The difficulty of the classes is evaluated separately, to determine whether you got a good GPA by taking only easy classes. Also, some high schools don’t offer Honors, AP and IB classes, so giving extra points for those classes would yield an unfair comparison between students at different schools.