How this instrument works
Semester Grade combines up to three separately weighted categories of coursework into a single overall percentage — each category's grade is multiplied by its own weight, and the three weighted contributions are added together and divided by 100. Grades of 88%, 92% and 79% weighted 40%, 40% and 20% respectively combine to (88x40 + 92x40 + 79x20) / 100 = (3520 + 3680 + 1580) / 100 = 87.8%.
Unlike a calculator built around a single 'current grade plus one final exam,' this instrument leaves the categories up to you — homework, quizzes, midterms, projects, participation, or any other breakdown your syllabus uses, as long as you can express each one as a percentage grade with its own weight. The three weights should add up to 100% between them, since together they're meant to describe the whole course.
If your syllabus only splits the grade into two categories, leave the third component's grade and weight at their 0/0 default — with a weight of 0, that slot contributes nothing to the total, so the formula behaves exactly like a two-category calculation without any extra steps.
- Enter the grade (%) and weight (%) for your first grading category — homework, exams, or whatever your syllabus calls it — into Component 1.
- Repeat for Component 2 with your second category's grade and weight.
- If your syllabus has a third category, fill in Component 3 the same way; otherwise leave it at its 0/0 default.
- Make sure the weights you enter add up to 100% across however many components you're using.
- Overall grade updates automatically as the weighted combination of every component entered.
Worked example — three weighted categories totaling 100%
Enter 88% at a 40% weight for the first category, 92% at a 40% weight for the second, and 79% at a 20% weight for the third. The weighted contributions are 88x40 = 3520, 92x40 = 3680 and 79x20 = 1580, which sum to 8780. Dividing by 100 gives Overall grade = 87.8%.
The lightest-weighted category, 79% at only a 20% weight, pulls the overall grade down less than its raw percentage might suggest, since it counts for just a fifth of the total — the two 40%-weighted categories, both in the high 80s and 90s, dominate the final figure instead.
Questions
How is the overall semester grade calculated from weighted categories?
Multiply each category's grade by its weight, add the three results together, and divide by 100. For grades of 88%, 92% and 79% weighted 40%, 40% and 20%, that's (88x40 + 92x40 + 79x20) / 100 = 8780/100 = 87.8%. Dividing by 100 converts the weighted sum, expressed in percentage-points, back into a plain overall percentage.
What if my course only has two grading categories, not three?
Leave the third component's grade and weight at their 0/0 default. Since a weight of 0 multiplies to 0 regardless of the grade entered there, that unused slot contributes nothing to the total, and the formula collapses cleanly into a two-category weighted average using just the first two components you filled in.
Do the three weights need to add up to exactly 100%?
They should, since the weights are meant to represent the entire course as percentages of 100. If your weights sum to something other than 100 — say your syllabus lists percentages that only cover part of the grade — the result will be a weighted sum that doesn't correspond to a clean overall percentage, so double-check your syllabus's category breakdown first.
How is this different from a 'current grade plus final exam' calculator?
That style of calculator assumes exactly two inputs: a running current grade and a single final exam, each with its own weight. This instrument is more general — it accepts up to three independently named categories, so it fits syllabi that split the grade into homework, midterms and a final, or any other three-part breakdown, rather than forcing everything into a 'before the final' versus 'the final' split.
Can I use this for any weighting scheme, not just homework, exams and projects?
Yes — the calculator doesn't care what you call each category, only the grade and weight you assign it. Participation, labs, presentations, a midterm, or any other graded component works the same way, as long as you can express it as a percentage grade with a percentage weight and the weights you're using add up to 100 across however many categories you fill in.