How Weighted Grades Work (With Worked Examples)
Written by the MicroTools Hub team · Updated
Most university courses do not average every mark equally. Instead, each category (assignments, quizzes, a midterm, a final) is worth a stated percentage of the course. This guide explains the arithmetic, shows two worked examples, and lists the mistakes that most often lead to a wrong answer.
Related tools: Grade Calculator, Target Score Calculator. They run in your browser, with no account.
The core idea: weight times score
A weight says how much of your final course grade a category controls. If the midterm is worth 30%, then a perfect midterm contributes 30 percentage points to your course total, and a midterm score of 70% contributes 0.70 × 30 = 21 points.
Your course grade is the sum of those contributions. When every category has been marked and the weights add up to 100%, that sum is your final percentage.
Example: Assignments 20% at 90%, quizzes 10% at 80%, midterm 30% at 70%, final 40% at 85%. Points: 18 + 8 + 21 + 34 = 81. The course grade is 81%.
Marks out of a maximum
Marks are often out of different totals. Convert each one to a percentage first: earned ÷ maximum. A mark of 27 out of 30 is 90%; 68 out of 80 is 85%. Then multiply by the weight. Adding raw marks together only works if every mark is out of the same total, which is rarely true across categories.
Your grade so far when some work is not marked yet
Partway through a course you have only some of the marks. Two different numbers are useful, and mixing them up causes most confusion:
- Points banked: the contributions you have already earned toward the whole course. In the example above, after the first three categories you have 18 + 8 + 21 = 47 points.
- Current grade on graded work: points banked ÷ weight that has been graded × 100. Here that is 47 ÷ 60 × 100 = 78.3%. This tells you how you are doing so far, not where you will finish.
Common mistakes
- Averaging category averages without weights. A strong quiz average does not rescue a weak final if the final is worth four times as much.
- Weights that do not total 100%. If your syllabus lists 95% of the weights, an assessment is missing. A good calculator tells you instead of quietly assuming the gap is zero.
- Forgetting dropped scores, bonus marks or minimum-pass rules. Many syllabi drop the lowest quiz or require a minimum mark on the final. Simple weighted calculators cannot know your course's special rules, so check the syllabus.
- Treating an unmarked item as a zero. Leaving it out of your current grade and counting it as zero answer different questions.
From percentage to GPA
A percentage is not a GPA. Institutions convert percentages to letter grades or grade points using their own scales, and the scales differ between countries and even between schools. A common US scale maps 93% and above to an A (4.0) and 90–92% to an A− (3.7), but yours may not match. Use the scale published by your institution, and weight GPA by credit hours, not by simple averaging.
Try it with your own numbers
The weighted grade calculator on this site lets you enter earned and maximum marks, shows the formula it used, and warns when your weights do not add up to 100%. Nothing you enter leaves your browser.
This guide is general information for study purposes. Check your institution's own requirements, which take priority.