# How to Calculate Weighted Grade Average

GradeGrid allows you to easily separate grades into separate grading categories. Each grading category can then be given a weight, and GradeGrid will automatically calculate the overall weighted grade average for you. If you would like to know how to calculate weighted averages by hand, please continue reading.

## Calculating Basic Averages

Calculating an overall grade average is simplest when all grades have the same weight. This can be accomplished by adding all of the grades together and dividing the sum by the total number of grades. For example, if all grades are on a 100 point scale, and a student receives a 95, 97, and a 64, the overall grade can be calculated as (95 + 97 + 64) / 3. The result is 85.33 for the student's overall grade.

## Calculating Weighted Averages

In cases where grades don't share the same weight, ie. when multiple grading categories exist, the calculation is a little more complicated. The weight of each grade category must be taken into account. Individual grades might also be worth different amounts within a given category. Consider the following example:

Category Weight
Homework 20
Quizzes 30
Tests 50
Homework 9/10 8/10 7/10
Quizzes 50/60 45/60 92/100
Tests 90/100 88/100 47/50

To calculate the weighted average, we need to do the following:

1. Calculate the grade average within each category.

Individual Category Averages
Category Calculation Result
Homework (9 + 8 + 7) / (10 + 10 + 10) .80
Quizzes (50 + 45 + 92) / (60 + 60 + 100) .85
Tests (90 + 88 + 47) / (100 + 100 + 50) .90

2. Multiply each category average by its corresponding weight.

Category * Weight
Category Calculation Result
Homework .80 * 20 16
Quizzes .85 * 30 25.5
Tests .90 * 50 45

3. Calculate the sum of the category weights.

Sum of Weights
Calculation Result
20 + 30 + 50 100

4. Add the weighted categories together and divide by the sum of the weights.

Overall Average
Calculation Result
(16 + 25.5 + 45) / 100 .865

Congratulations, you now know that the student scored an overall grade of 86.5%