Because different assignments require different amounts of effort and are valued differently, it is important for teachers to give larger assignments more weight in the grade book. To calculate weighted grades, teachers and their students must know the comparative values of the different assignments and how the points are assigned.
- Start with a standard
Every weighted grade system needs a point of reference. Other grades can be compared to that standard. For example, an essay in an English class might be worth 100 points and not weighted, or it could be described as weighted at a value of 1.0. A 91 percent grade on the assignment appears as 91 points when the weighted grade is calculated.
- Assign weight to assignments
Teachers may want to grade a project out of 100 so they can easily input a percentage, but they might want that project to be valued higher than an essay. In that case, the project might be weighted at 3.0, which means that its value is counted three times when the term grade is calculated. Similarly, a small assignment might be weighted at 0.5. The weights should be easy numbers to multiply, such as whole numbers no greater than five or the fraction 1/2.
- Calculate the average
Calculate each grade in terms of a percentage, and multiply that percentage by the weight of that assignment. Add all of those numbers together, and divide that sum by the sum of the total weight. For example, if a student's assignments were three non-weighted assignments with scores of 91/100, 89/100 and 78/100, and one project at weight 3.0 of score 97/100, then the average grade would be 90.17%. The formula for this calculation looks like this: (91% + 89% + 78% + 3*97%)/(1 + 1 + 1 + 3) = (541%)/6 = 90.17%.