Calculating grades by weight
This page is for the search that sounds like homework help. You get a plain sequence — convert percents, multiply, add, divide — and the same calculator as the weighted tool underneath so you can check your pencil math.
GRADE CATEGORIES
Name · score · share of course
COURSE PERCENT
——
Enter numbers and calculate.
Planning math only — not your school gradebook
When to use — and when not to
When to use
Teacher said “show your work”; parent helping with a progress report; you understand averages but not weights.
When not to
You already live in category rows and just need speed → weighted grade calculator. You need final-only reverse math → final grade calculator.
Assumptions
Same weighted-average engine. Walkthrough uses percents, not points-out-of, unless you convert first (earned/possible × 100).
How it works
contribution_i = score_i × weight_i course% = Σ contribution / Σ weight
- List each category score as a percent.
- Write each weight as a decimal (20% → 0.20) or keep percents and divide by 100 at the end.
- Multiply score × weight for each row.
- Add the products.
- If weights ≠ 100, divide by total weight.
Examples
90 @ 40%, 80 @ 60%
36 + 48 = 84%
Smallest useful weighted example — two rows.
100 @ 10%, 70 @ 40%, 85 @ 50%
10 + 28 + 42.5 = 80.5%
Gotchas
- Mixing points and percents in one table breaks the story — convert everything to % first.
- Weight written as “2” meaning 20% — confirm units.
- Forgetting to divide when weights are credits (3 and 4 credit rows) — that is GPA land, not this page.
- Rounding mid-step can drift a tenth; keep two decimals until the end.
Compare
Calculator-first UI? → weighted grade calculator.
Equal weights? → grade average calculator.
Letter at the end? → percentage to letter grade.
Related
FAQ
How much that category counts toward the course total, usually as a percent on the syllabus.