How to calculate a weighted grade
Multiply each score by its weight, add the products, and divide by the total weight. Homework 92 (20%), midterm 78 (30%), final 85 (50%): (92 × 20 + 78 × 30 + 85 × 50) ÷ 100 = 84.3.
Weights don’t have to sum to 100. For a GPA, use credit hours as weights and grade points as values: A (4.0) in a 4-credit course and B (3.0) in a 3-credit course gives (16 + 9) ÷ 7 ≈ 3.57.
When a plain mean is wrong
If you average class averages from classes of different sizes, or prices paid for different quantities, a plain mean gives small groups too much influence. Weighting by size or quantity fixes that. The calculator shows the unweighted mean too, so you can see the difference.
Frequently asked questions
What grade do I need on the final?
Rearrange: required = (target − current weighted points) ÷ final weight. With 60% of the course done at an 80 average and a 40% final, to finish on 85 you need (85 − 0.6 × 80) ÷ 0.4 = 92.5.
Do the weights need to be percentages?
No. Any positive numbers work: percentages, credits, counts or hours. The calculator divides by their total.