In each of my classes I use a weighted average to compute student grades. Assignments are divided up into categories like exams, homework, and labs. Each category is assigned a weight as a percent of the total grade with each assignment within that category having equal weight. I’ve noticed that students often struggle understanding their grades when dealing with these kinds of weighted averages. In this post we’ll look at how one can understand how a single assignment will impact their final grade in such a grading system.

### Single Assignment Weight

Let’s say that exams are worth 35% of your grade and that there are a total of 7 exams. Each individual exam is worth 5% of your total grade because each exam is an equally weighted so the 35% category weight is equally distributed amongst the exams. What would the weight of a homework assignment be if homework was 25% of your grade and you had 8 homework assignments? In this case we take 25/8 to get 3.125% per homework assignment. In general, the weight of an assignment is equal to the weight of the assignment’s category divided by the number of assignments in the category.