To calculate your grade, turn each score into a percentage, multiply it by the weight of that item, add the results, and divide by the weight you have graded so far. The made-up course in this guide stands at 80.71% with 30% of the grade still to come. To finish on 80%, the student needs 78.4% on what is left.
- Percentage = points earned ÷ points possible × 100.
- A weighted grade multiplies each percentage by its weight, then adds them up.
- A plain average of scores is wrong when items have different weights.
- If the final is still to come: needed score = (target − current × share graded) ÷ final weight.
- Cut-offs for A, B and C differ by school, so check your syllabus.
Step 1: Turn each score into a percentage
Divide the points you earned by the points possible, then multiply by 100. A quiz scored 41 out of 50 is 41 ÷ 50 × 100 = 82%. If the score is already a percentage, leave it as it is.
Step 2: Find the weight of each item
Your syllabus lists how much each part of the course counts toward the final grade. Quizzes might be 15%, a midterm 30% and a final exam 30%. The weights usually add up to 100%.
Step 3: A worked example
Here is a made-up intro psychology class. Three items are graded, and the final exam is still to come.
| Item | Score | Percentage | Weight | Points toward the grade |
|---|---|---|---|---|
| Quizzes | 41 out of 50 | 82.0% | 15% | 12.30 |
| Lab reports | 88 out of 100 | 88.0% | 25% | 22.00 |
| Midterm | 74 out of 100 | 74.0% | 30% | 22.20 |
Each item’s contribution is its percentage multiplied by its weight. Adding them gives 56.50 points of the course grade. Those items carry 70% of the grade. To get your current grade, divide the points by the share graded: 56.50 ÷ 0.7 = 80.71%.
Why a plain average gives the wrong answer
Suppose a student scores 90% on an item worth 10% and 60% on one worth 90%. The plain average is 75%. The weighted grade is 63.0%, because the second item carries nine times the weight. Always multiply by the weights.
Step 4: What the rest of the course must deliver
The graded items have locked in 56.50 points out of 100. The final exam is worth 30%, so the best possible grade is 86.5% and the worst is 56.5%. If the student wants 80%, the formula is (80 − 56.50) ÷ 0.3 = 78.3, so the student needs 78.4% on the final.
| Score on the final | Course grade |
|---|---|
| 100% | 86.5% |
| 90% | 83.5% |
| 80% | 80.5% |
| 70% | 77.5% |
| 60% | 74.5% |
| 50% | 71.5% |
Aiming higher changes the answer. For 85%, the student would need 95.0% on the final.
A final worth a lot
When the final is a large share, one exam can move the grade a long way. Student A has 78.4% and the final is worth 35%. The final needs to be 83.0% for a B and 54.4% for a C. An A needs 111.5%, which is above 100, so an A is out of reach without extra credit. The formula is (target − current × (1 − weight)) ÷ weight.
Groups of small items
Homework and quizzes often count as one group. Add the points earned across the group and divide by the points possible. Eight homework sets scored 9, 8, 10, 7, 9, 10, 8 and 9 out of 10 give 70 ÷ 80 = 87.5%. If the group is worth 20% of the course, it adds 87.5 × 0.20 = 17.5 points to your grade. Enter the group once, with its total weight.
When the lowest score is dropped
Some syllabi drop the lowest quiz. Take five quizzes scored 18, 14, 20, 17 and 19 out of 20. Without a drop they total 88 out of 100, or 88%. Drop the 14 and you have 74 out of 80, which is 92.5%. The rule can lift a group by several points, so read the policy before you work out your grade.
Extra credit
Extra credit adds points without adding to the points possible, so a score can pass 100%. Some instructors cap the total, and some add it to the final grade only. Check how yours is counted before you plan around it.
Points-based courses
Some courses add up points instead of weights. Add the points you have earned and divide by the points possible so far. A student with 412 points out of 500 has 412 ÷ 500 = 82.4%. Use the same idea to plan: if the whole course is 1,000 points, 800 points makes 80%.
From percentage to letter
A common scale is A at 90, B at 80, C at 70 and D at 60. Many schools differ, so check yours. The cut-offs also change between countries, and between universities in the same country.
| University | Band | Range |
|---|---|---|
| ANU (Australia) | High Distinction | 80 to 100 |
| ANU (Australia) | Distinction | 70 to 79 |
| Macquarie (Australia) | Distinction | 75 to 84 |
| UBC (Canada) | A | 85 to 89 |
| UBC (Canada) | A+ | 90 to 100 |
A mark of 72 is a Distinction at ANU, but it falls below the Macquarie Distinction band of 75 to 84. Pass marks differ too. UBC sets the pass mark at 50% in most faculties, and Cardiff sets 40% for most undergraduate modules.
Common mistakes
- Averaging scores. Weight each one first.
- Counting work not yet graded. Leave it out of your current grade, then plan for it.
- Weights that do not add to 100. Check the syllabus for missing items.
- Dropping the lowest score without checking. Some courses drop one quiz, so read the policy.
- Rounding too soon. Round the final answer only.
Check your result
Compare your result with the grade shown in your course portal. A gap of a point or two often means the portal rounds, applies a drop rule or has an item the syllabus does not mention. A larger gap suggests a missing score or the wrong weight. Ask your instructor before the final.
Calculators that help
- Grade Calculator: your current course grade and the average you need.
- Final Grade Calculator: the score you need on a final for each letter.
- Test Grade Calculator: the percentage and letter for one test.
Questions students ask
How do I calculate my grade with weights?
Convert each score to a percentage, multiply by its weight, add the results, and divide by the total weight that has been graded.
How do I calculate the grade I need on a final?
Use (target − current × (1 − final weight)) ÷ final weight. With 78.4% and a final worth 35%, a B needs 83.0%.
How do I turn points into a percentage?
Divide the points earned by the points possible, then multiply by 100.
Why is my grade different from the portal?
The portal may round, drop a low score, or use a weight or item you left out. Compare each item with your syllabus.
Can I calculate my grade before the final?
Yes. Work out your current grade from the items already marked. Then use the weight of the final to see the score you need for each target. The result is a plan, not a prediction, because the final can go either way.
What does weight mean in a course?
Weight is the share of your final grade that an item is worth. A midterm weighted at 30% counts for 30 of the 100 points available in the course.
What is the pass mark?
It depends on the school. UBC sets 50% in most faculties and Cardiff sets 40% for most undergraduate modules. Check your own regulations.
