Student guide
How weighted grades work
In a weighted course, some categories count more than others. A final exam worth 50% moves your grade far more than homework worth 20%, so a simple average of your scores can be misleading.
Step 1: turn each score into a percentage
Divide the points you earned by the points possible, then multiply by 100.
Score % = points earned ÷ points possible × 100
43 out of 50: 43 ÷ 50 × 100 = 86%
The what percent is one number of another calculator does this step for you.
Step 2: multiply by the weight and add up
Multiply each category's percentage by its weight as a decimal, then add the results. The weights should total 100%.
Final grade = (score₁ × weight₁) + (score₂ × weight₂) + …
| Category | Weight | Your score | Counts for |
|---|---|---|---|
| Homework | 20% | 92% | 92 × 0.20 = 18.4 |
| Midterm | 30% | 78% | 78 × 0.30 = 23.4 |
| Final exam | 50% | 85% | 85 × 0.50 = 42.5 |
| Total | 100% | 84.3% |
Your current grade before the final
Partway through a course, divide what you have earned so far by the weight that has been graded so far.
Homework and midterm are done: 18.4 + 23.4 = 41.8 points out of a possible 50.
41.8 ÷ 0.50 = 83.6% current grade
What do I need on the final?
Subtract what you already have from the grade you want, then divide by the final's weight.
Needed = (target − points so far) ÷ final weight
For 90% overall: (90 − 41.8) ÷ 0.50 = 96.4% on the final
For 80% overall: (80 − 41.8) ÷ 0.50 = 76.4% on the final
If the answer is above 100%, the target can't be reached with the final alone. If it is below 0%, you have already secured it.
Common mistakes
- Averaging the percentages. (92 + 78 + 85) ÷ 3 = 85%, but the weighted grade is 84.3%, because the lower midterm and final count for more than homework.
- Forgetting to divide by 100. Multiply by 0.30, not 30, or your total will be 100 times too big.
- Mixing points and weights. Some courses simply add all points earned and divide by all points possible. Check your syllabus to see which method your teacher uses.
Teachers may also drop the lowest score, curve results, or round differently, so your official grade can differ slightly from these calculations.