To calculate a weighted percentage, first multiply each item by the percentage it has been allotted, and then add those values together. Weighted percentages help in situations where certain factors are more important than others.
As an example, a teacher might inform his or her students that the year's grade will be based on tests that will be worth 50 percent of the grade, quizzes that will count for 30 percent and homework assignments that will count for the remaining 20 percent of the grade. If a student had a 95 percent average on the tests, a 90 percent average on the quizzes and a 100 percent average on the homework assignments, the weighted percentage would be calculated as follows: "(95 x 0.5) + (90 x .3) + (100 x .2) = 47.5 + 27 + 20 = 94.5". The final grade for the student would be 94.5 percent .