United States school systems commonly use the letter grade scale from “A” to “F,” with “A” being the highest grade. The cumulative numerical average refers to an average grade obtained by a student for classes taken. To determine this average all grades earned are converted to numbers using the following scale - “A”=4, “B”=3, “C”=2,”D”=1 and “F”=0. Grade Point Average (GPA) is another commonly used numeric average that takes into account not only the grade but also the number of course credit hours.

## Calculating Cumulative Grade Numerical Average

Convert the course grades into the numeric scale. For example, a student took three classes and earned the following grades "A," "A" and "B." Those grades correspond to 4, 4 and 3 on the numeric scale.

Add up all numeric grades; in this example, the sum is 4 + 4 + 3 = 11.

## Sciencing Video Vault

Divide the sum by the number of classes taken to calculate the cumulative numerical average. In this example, the cumulative numerical average is 11 / 3 = 3.66667.

Round the cumulative numerical average to the third decimal place; in this example, the result is 3.667.

## Calculating Grade Point Average (GPA)

Convert the course grades into the numeric scale. For example, a student took three classes with 3,1 and 3 credit hours, respectively, and earned the following grades "A," "B" and "C." Those grades correspond to 4, 3 and 2 on the numeric scale.

Multiply the grade by the credit hours for the respective course to calculate grade points. In this example, the the grade points for each course are 12 (4 x 3), 3 (3 x 1) and 6 (2 x 3).

Add up all grade points. In this example, the sum is 12 + 3 + 6 = 21.

Add up all credit hours. In this example, the total credit hours are 3 + 1 + 6 = 7.

Divide the total number of grade points by the total number of credit hours to calculate GPA. In this example, GPA is 21 / 7 = 3.