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 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.
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||Grade 1||Grade 2||Grade 3|
To calculate the weighted average, we need to do the following:
1. Calculate the grade average within each category.
|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.
|Homework||.80 * 20||16|
|Quizzes||.85 * 30||25.5|
|Tests||.90 * 50||45|
3. Calculate the sum of the category weights.
|20 + 30 + 50||100|
4. Add the weighted categories together and divide by the sum of the weights.
|(16 + 25.5 + 45) / 100||.865|
Congratulations, you now know that the student scored an overall grade of 86.5%
The above steps should enable you to calculate weighted grading averages by hand. If you are looking for an easier way to automatically calculate student grades, please check out our grading software. The screenshot below shows the same calculation using GradeGrid.