To calculate a grade percentage, divide the points earned (or correct answers) by the total points possible, then multiply by 100. If a course has weighted categories, multiply each category's average by its weight and add the results instead of averaging every score equally.
Two ways to get a percentage grade
Every percentage grade comes from the same relationship — points earned against points possible — but the inputs differ depending on how the assessment was scored.
- Wrong-answers method: percentage = 100 × (total questions − wrong answers) ÷ total questions. Use this when every question is worth the same amount.
- Points-earned method: percentage = (points earned ÷ points possible) × 100. Use this for rubrics, essays, and assignments with uneven point values.
Quick checks: converting common scores
Missing 7 of 40 questions leaves 33 correct, which works out to 82.5%. A raw score of 27 out of 40 is 67.5%, and 75 out of 80 is 93.75%. Once you have the percentage, compare it against your school's grading scale to find the letter grade — the standard scale starts an A at 93% and a passing grade at 60%, but see the full US grading scale for every threshold and GPA value, since schools vary.
Combining weighted categories into one grade
A single percentage only tells you about one test. Most courses combine several graded categories — homework, quizzes, exams — each worth a different share of the final grade. Multiply each category's average by its weight, then add the weighted results together. The category weights should total 100% for the overall percentage to be accurate.
| Category | Score | Weight | Weighted value |
|---|---|---|---|
| Homework | 90% | 20% | 18.0 |
| Quizzes | 85% | 30% | 25.5 |
| Midterm | 80% | 30% | 24.0 |
| Final exam | 70% | 20% | 14.0 |
Solving backward for the score you need on the final
Sometimes the question runs in reverse: given a current grade and a target grade, what score does the final exam need? The weighted average formula still applies — it's just solved for the missing final-exam score instead of the overall percentage. With a current grade of 84%, a final exam worth 30% of the course, and a target of 90% overall, the final exam needs to reach about 98.2%. A lower current grade or a lighter final-exam weight pushes that required score higher.
Using a calculator instead of doing it by hand
For a single test or assignment, the grade calculator converts wrong answers or points into a percentage and letter grade directly. For a full course with multiple weighted categories, the gradebook calculator adds each category and its weight, then computes the overall percentage automatically — the worked example above is its default state, so you can open it and see the same 81.5% result. If you already know your current grade and want the exact score needed on what's left, the final grade calculator solves that in one step.
Grade Calculator Editorial Team
We create plain-language grading tools and educational guides, check every worked example against the underlying formula, and note where school or instructor policies can change the result.