Quick answer: To calculate a grade, divide the points you earned by the points possible and multiply by 100. If your course uses weights, multiply each category’s percentage by its weight, add the results, and divide by the total weight of the work completed so far.
You open the gradebook, see a handful of scores, and wonder what they actually add up to. Or the final exam is next week and you need to know exactly what score keeps you at a B. Either way, the maths is basic arithmetic, but the small rules around weights, dropped scores and missing work are where most people go wrong. This guide shows each case with real numbers you can check yourself.
In short
- Percentage grade = points earned ÷ points possible × 100.
- Weighted grade = Σ (category % × weight) ÷ Σ weights.
- Mid-term, divide only by the weights of the work that has been graded.
- Final exam needed = (target grade − current weighted points) ÷ final exam weight.
- Your syllabus is the final authority on weights, drops and rounding.
Table of Contents
How to calculate a basic percentage grade
If every assignment counts for its points, add up what you earned, add up what was possible, and divide.
Grade % = (Points earned ÷ Points possible) × 100Some quick examples:
| Score | Calculation | Grade |
| 12 out of 15 | 12 ÷ 15 × 100 | 80% |
| 25 out of 30 | 25 ÷ 30 × 100 | 83.33% |
| 425 out of 500 | 425 ÷ 500 × 100 | 85% |
To combine several scores in a points-based course, do not average the percentages. Add all the earned points and all the possible points first. Suppose assignments are 150 out of 180, quizzes are 40 out of 50, the midterm is 82 out of 100, and the final is 165 out of 200:
(150 + 40 + 82 + 165) ÷ (180 + 50 + 100 + 200) = 437 ÷ 530 = 82.45%In a points system, bigger assessments count more automatically, because they are worth more points.
How to convert a percentage into a letter grade
Once you have the percentage, your school’s scale turns it into a letter. A common US scale looks like this:
| Percentage | Letter grade | Grade points |
| 93 – 100 | A | 4.0 |
| 90 – 92 | A- | 3.7 |
| 87 – 89 | B+ | 3.3 |
| 83 – 86 | B | 3.0 |
| 80 – 82 | B- | 2.7 |
| 77 – 79 | C+ | 2.3 |
| 73 – 76 | C | 2.0 |
| 70 – 72 | C- | 1.7 |
| 67 – 69 | D+ | 1.3 |
| 60 – 66 | D | 1.0 |
| Below 60 | F | 0.0 |
Schools differ. Some have no plus or minus grades, some draw the A line at 90, and universities in India and Pakistan often use their own marks-to-grade tables. Always use the scale printed in your syllabus or handbook. Once you have grades, the next step is turning them into a semester average, which is covered in how to calculate GPA.
How to calculate a weighted grade
Most courses do not count every score equally. The syllabus says something like “homework 20%, quizzes 10%, project 20%, midterm 20%, final 30%.” That is a weighted system, and the formula is:
Weighted grade = Σ (Category score × Weight) ÷ Σ WeightsIf all the weights are in place and add up to 100%, the bottom line is just 100%, so you simply add the weighted scores. Follow these steps:
- Find the weight of every category in your syllabus.
- Work out your percentage in each category (points earned ÷ points possible).
- Multiply each percentage by its weight.
- Add the results.
- Divide by the total weight of the categories you have included.
How to calculate your current grade mid-term
This is the question most students actually have: “What is my grade right now?” The trick is to divide only by the weights of the work that has been graded, so that missing work is not counted as zero. Here is a student part-way through a course:
| Category | Weight | Your score | Weighted points |
| Homework | 20% | 88% | 17.6 |
| Quizzes | 10% | 92% | 9.2 |
| Project | 20% | 85% | 17.0 |
| Midterm | 20% | 76% | 15.2 |
| Final exam | 30% | not taken | |
| Graded so far | 70% | 59.0 |
Current grade = 59.0 ÷ 0.70 = 84.29%That is a current grade of about 84.3%, which is a B on the scale above. Notice what would go wrong if you divided by 100% instead: 59.0 would look like a failing grade, because the 30% final has not been counted yet.
The simple-average trap
The most common calculation mistake is averaging category scores as if they were equal. For the same student, the four scores average (88 + 92 + 85 + 76) ÷ 4 = 85.25%, but the real weighted grade is 84.29%. The gap appears because the midterm, their weakest score, is worth 20% while the quizzes, their strongest, are worth only 10%. It can be much larger in other classes. Imagine 100% on homework worth 10% and 60% on tests worth 90%: the simple average says 80%, but the true grade is 64%.
You can do all of this with the Weighted Grade Calculator instead of by hand.
Points-based vs weighted grading: which is yours?
| Points-based | Weighted by category | |
| How it works | Add all points earned and all points possible | Each category has a percentage weight |
| Example syllabus line | “Total of 500 points” | “Tests 50%, homework 30%, quizzes 20%” |
| Big assessments count more because | They are worth more points | The syllabus says so |
| Formula | Earned ÷ possible × 100 | Σ (score × weight) |
Check your syllabus before you calculate. The same set of scores can give two different grades under the two systems.
What do you need on the final exam?
Rearrange the weighted formula to solve for the one score you do not have yet:
Final needed = (Target grade − Weighted points so far) ÷ Final exam weightUsing the same student, with 59.0 weighted points so far and a final worth 30% (0.30):
| Target for the course | Calculation | Score needed on the final |
| 80% (B-) | (80 − 59.0) ÷ 0.30 | 70% |
| 85% (B) | (85 − 59.0) ÷ 0.30 | 86.7% |
| 90% (A-) | (90 − 59.0) ÷ 0.30 | 103.3% |
So this student needs a 70% to hold a B-, an 86.7% to reach a B, and cannot reach an A- unless the instructor offers extra credit, because it would take more than 100% on the final. That last line is the useful kind of bad news: you learn it a week before the exam, not after. The Final Grade Calculator runs this for any target.
What happens when the lowest score is dropped?
Many instructors drop the lowest quiz or homework. The calculation is the same, just without that score and its points. Say there are five quizzes, each out of 10, and you scored 8, 10, 6, 9 and 7:
With all five: 40 ÷ 50 = 80%
Dropping the 6: 34 ÷ 40 = 85%
The drop is worth five percentage points on the quiz category. Check the syllabus for whether the drop applies to the lowest score or the lowest percentage, and whether it is automatic or has to be requested.
How extra credit works
Extra credit adds points to your earned total without adding to the possible total, or adds a small bonus to a category. If you scored 45 out of 50 on a test and the instructor offers 3 bonus points, the result is (45 + 3) ÷ 50 = 96%, up from 90%. Each instructor decides whether extra credit can push a category above 100%, so ask before you count on it.
How curves change your grade
A curve is any adjustment applied to the whole class. The two most common types give different results for the same score:
| Curve type | How it works | A raw 72 becomes |
| Flat add | Everyone gets the same bonus points (here +5) | 77 |
| Scale to the top score | Top score is set to 100 (here the top is 92): score ÷ 92 × 100 | 78.3 |
Curves are the instructor’s choice, so never assume one. Calculate your grade on the raw scores, then adjust if the curve is announced.
What does one missing assignment do to your grade?
A zero for missed work does far more damage than most students expect. If you score 90% on four equal assignments and miss the fifth, your average is (90 × 4 + 0) ÷ 5 = 72%. One zero has pulled a high A- to a C-. That is why checking for missing work and asking about late submissions early is one of the best uses of your time. If you want a plan to bring a grade back up, see how to raise your GPA.
Common mistakes when calculating grades
- Averaging percentages instead of weighting them. The result is wrong whenever categories have different weights.
- Dividing by 100% in the middle of the term. Divide by the weights of graded work only.
- Treating ungraded work as zero. It makes your current grade look far worse than it is.
- Ignoring dropped scores and extra credit. Both can change a category by several points.
- Rounding too early. Keep two decimals until the final answer, then follow your instructor’s rounding rule.
- Using the wrong grade scale. An 89.6% may be a B+ or an A- depending on the school.
- Planning around a curve that was never announced.
Frequently asked questions about calculating grades
How do you calculate your grade?
Divide the points you earned by the points possible and multiply by 100. If the course is weighted, multiply each category’s percentage by its weight and add the results.
How do you calculate a weighted grade?
Weighted grade = Σ (category score × weight) ÷ Σ weights. Use the weights from your syllabus. The Weighted Grade Calculator does it automatically.
How do you calculate your grade mid-semester?
Add up the weighted points for the work that has been graded, then divide by the total weight of that graded work, not by 100%.
How do you calculate the grade you need on the final?
Final needed = (target grade − weighted points so far) ÷ final exam weight. If the answer is over 100%, the target is out of reach without extra credit.
How do you calculate a percentage grade?
Points earned ÷ points possible × 100. For example, 425 out of 500 is 85%.
What is an 85% as a letter grade?
On the common US scale, 85% is a B. Some schools give a B or B+ depending on their cut-offs, so check yours.
How does a dropped lowest score change my grade?
The lowest score and its possible points are removed, which raises the category average. In the quiz example above, the grade rose from 80% to 85%.
How do you calculate your grade with extra credit?
Add the bonus points to your earned points without adding them to the possible points, unless your instructor says otherwise.
What is the difference between a grade and a GPA?
A grade measures one course. GPA averages the grades from many courses, weighted by credit hours. See how to calculate GPA.
How do you convert marks to a CGPA?
Convert marks to grade points using your university’s table, then apply the credit-weighted formula. The CGPA to Percentage tool and College GPA Calculator help with the next step.
Final thoughts
Calculating a grade is arithmetic plus two habits: read the syllabus for weights and drops, and divide by the right total. Do that, and you can check any gradebook, predict any final result and know exactly what the next exam must deliver. When you want the numbers done for you, try the Weighted Grade Calculator and the Final Grade Calculator.
Sources
- Grade Calculator, Omni Calculator
- Grade Calculator, CalculatorSoup
- Free Grade Calculator, GPACalculator.net
- Calculating weighted grades, Northern Arizona University
Related Calculators
- Weighted Grade Calculator: category weights, done for you
- Final Grade Calculator: the score you need on the final
- College GPA Calculator: turn grades into GPA
Learn More
- How to Calculate GPA: the formula, with worked examples
- How to Raise Your GPA: habits that turn into grades
- CGPA vs SGPA: the key differences, explained