How to calculate a weighted grade
Multiply each category average by its weight, add the results, and divide by the total weight completed so far. A worked example with homework, quizzes, a midterm and a final.
Weighted grade = sum of (category score × weight) ÷ sum of weights used. With homework 92% (20%), quizzes 85% (15%) and a midterm 78% (25%), the weighted grade so far is 50.65 ÷ 60 = 84.4%. Divide by the weights you’ve completed, not by 100, until every category has a score.
On this page
In a weighted course, each category counts for a set share of your grade, no matter how many points it contains.
weighted grade = Σ(category score × weight) ÷ Σ(weights)
Worked example
| Category | Weight | Your average | Score × weight |
|---|---|---|---|
| Homework | 20% | 92% | 18.4 |
| Quizzes | 15% | 85% | 12.75 |
| Midterm | 25% | 78% | 19.5 |
| Final exam | 40% | not yet taken | — |
Add the weighted scores: 18.4 + 12.75 + 19.5 = 50.65. Add the weights used: 20 + 15 + 25 = 60. Your current grade is 50.65 ÷ 60 = 84.4%.
Try it: Homework: 20% of 92
Open in calculatorTry it: 50.65 weighted points out of 60
Open in calculator
Don’t divide by 100 too early
A common mistake is to divide 50.65 by 100 and conclude your grade is 50.65%. That treats the ungraded final as a zero. Until every category has a score, divide by the total weight completed.
When the final is in
Say you score 80% on the final. Add 80 × 0.40 = 32 weighted points. Total: 50.65 + 32 = 82.65 out of 100, so the course grade is 82.65%.
Notice that it went down from 84.4%. A score below your current average pulls the average down, and the final is worth 40% of the grade, so it pulls hard. To plan for this, see what score do I need on my final.
Weighted vs points-based grading
In a points-based course, every point counts equally. A 200-point final simply contributes 200 points to the total. In a weighted course, the final counts for its stated percentage even if it has only 50 points. The difference can be large when categories have very different point totals.
| Points earned | Points possible | |
|---|---|---|
| Homework | 460 | 500 |
| Exam | 39 | 50 |
Points-based: 499 ÷ 550 = 90.7%. Weighted with homework 20% and exam 80%: 0.2 × 92 + 0.8 × 78 = 80.8%. Same work, different grades, depending on the syllabus.
Dropped scores and empty categories
If the lowest quiz is dropped, remove it before averaging the quiz category. If a category is empty because nothing has been graded yet, leave both its score and its weight out of the calculation, as with the final above.
Checking your gradebook
Online gradebooks sometimes show a running total that doesn’t match the syllabus weights, especially early in a term. Recalculating with the method above tells you where you actually stand. For simple tests without weights, see test score percentage. For why averaging percentages without weights goes wrong, see average of percentages.
Questions
What if the weights don't add up to 100%?
Divide by whatever they add up to. The formula already does this: sum of (score × weight) ÷ sum of weights.
Are categories averaged by points or by assignment?
It depends on the course. Some average each assignment’s percentage equally; others add up points across the category. Your syllabus or gradebook will say.
The calculator links in this guide are checked against the PercentSwift calculator every time the site is built. How we calculate explains the rounding rules. If you spot a mistake, email hello@percentswift.com.
