Two ways to calculate a class grade
Teachers usually use one of two methods. With weighted categories, each category (homework, quizzes, tests) has a share of the grade. With points, every assignment adds its points to a running total.
Weighted categories
Grade = (G1 × W1 + G2 × W2 + …) ÷ 100
G = grade for a category (%), W = that category’s weight (%). The weights must total 100%.
Example: weighted categories
Homework 95% (weight 20%), quizzes 82% (30%), tests 78% (50%).
- Homework: 95 × 20 ÷ 100 = 19 points
- Quizzes: 82 × 30 ÷ 100 = 24.6 points
- Tests: 78 × 50 ÷ 100 = 39 points
- Grade: 19 + 24.6 + 39 = 82.6%, a B.
Points
Grade = total points earned ÷ total points possible × 100
Example: points
Lab 1: 42/50, lab 2: 18/20, midterm: 71/100, project: 36/40.
- Points earned: 42 + 18 + 71 + 36 = 167
- Points possible: 50 + 20 + 100 + 40 = 210
- Grade: 167 ÷ 210 × 100 = 79.52%, a C. It is a C, not a B: 79.52% is below the 80% cut-off.
Letter grades
Letters use the scale Florida law sets for public middle and high schools [1]. Each band starts at its published lower bound and nothing is rounded, so 89.99% shows as a B.
| Letter | Percent |
|---|---|
| A | 90–100 |
| B | 80–89 |
| C | 70–79 |
| D | 60–69 |
| F | 0–59 |
Schools set their own cut-offs, weights and rounding rules. Check your school’s scale before relying on a letter.
Questions
Weighted categories or points: which should I use?
Use weighted categories when your syllabus says things like “homework 20%, tests 50%”. Use points when the grade is simply total points earned out of total points possible, so a 100-point test counts more than a 10-point quiz.
What if my weights don’t add up to 100%?
The calculator shows the total and waits for you to fix it; it never rescales weights. A total other than 100% usually means a missing category. If you really want to average with weights that don’t total 100, use the weighted average calculator.
How do I enter several scores in one category?
Average them first (add them up and divide by how many there are), then enter that average as the category grade. If the category is graded by points, add the points earned and the points possible instead.
Can I enter extra credit?
Yes. In points mode, points earned can be higher than points possible. In weighted mode, a category grade can be above 100%.
How do I leave out a dropped score or an empty row?
Leave the row blank and it is ignored. Rows with only some fields filled in are flagged so you can finish them.
Is this the same as a semester grade?
It can be, if one set of weights covers the whole course. If your grade is built from grading periods and an exam, the semester grade calculator is a closer fit.