How to Calculate Weighted Grades

Weighted grading means some assignments count more than others. Learn the formula and how to use it on any syllabus.

What weights mean

On a weighted syllabus, each category (homework, tests, participation, final) has a weight — its share of the final grade. Weights usually add up to 100%.

The formula

Weighted average = Σ(score × weight) ÷ Σ(weight)

Multiply each category score by its weight, add the results, and divide by the total weight (divide by 100 if weights are percentages).

Worked example

Example: Homework average 88% (weight 20), quiz average 90% (weight 10), midterm 82% (weight 30), final 91% (weight 40). Weighted grade = (88×20 + 90×10 + 82×30 + 91×40) ÷ 100 = (1760 + 900 + 2460 + 3640) ÷ 100 = 87.6%.

What if weights don't add to 100?

Some syllabi show weights as points (e.g., 300 total points). The same formula works — just use the points as weights and divide by their total.

Why it matters

Weighting is why acing a low-weight homework set barely moves your grade, while a high-weight exam can change everything. Knowing the weights tells you where to focus.

Frequently asked questions

Is a weighted grade the same as an average?
No. A plain average treats every assignment equally; a weighted average lets high-weight items dominate.
How do I know each category's weight?
It is printed on your syllabus, usually as a percentage next to each category.
What does 20% weight mean?
That category contributes 20 points out of 100 to your final grade.

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