What this calculator does
Find out what score you need on your final exam to get the course grade you want. Enter your grade going into the exam, how much the final is worth, and the grade you're aiming for. The calculator works out the exam score you need. It also tells you if that goal is out of reach or already safe, and lists the score you'd need for an A, B, C and D.
Its second option works out the course grade itself. Most course grades are weighted averages, where some work counts more than other work. For example, a syllabus might count homework 20%, quizzes 20%, the midterm 25% and the final 35%. Each category's average then counts in line with its weight. The calculator combines up to six categories this way and shows what each one adds. If some work isn't graded yet, it shows the average you need on the rest for each letter grade.
Where it's used
Why this math matters outside the classroom:
- Final exam target. A student with an 85 average on 75% of the grade needs a 65 on a final worth 25% to finish with 80.
- Weighted categories. Students combine homework, quiz and test averages using the weights in a course syllabus.
- Teacher gradebooks. Teachers check a gradebook's weighted average for a student by hand.
- Missing work. Students see how much a missing assignment lowers a category average and the overall grade.
Grade level and standards: Grade 7; Common Core State Standards for Mathematics 7.EE.B.4.a. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Choose Score needed on the final (the default), or Weighted course grade to combine category scores.
- For the final, enter your current grade, how much the final exam is worth, and the course grade you're aiming for.
- For a weighted grade, pick how many categories you have. Then enter each category's average score and its weight from your syllabus. Leave a row blank to skip it.
- Read the answer and the steps. The letter grade uses a common 90/80/70/60 scale, which your course may not use.
What the inputs mean
- Number of categories
- How many category rows to show, up to six.
- Category 1: score
- Your average percent in that category, such as 92 for 92%. Scores over 100 are allowed for extra credit.
- Category 1: weight
- How much of the course grade this category is worth, as a percent. If your weights add up to less than 100%, the answer is your grade on the work graded so far.
- Current grade before the final
- Your course grade on everything except the final, as a percent.
- Weight of the final exam
- How much of the course grade the final exam counts for. It must be more than 0% and no more than 100%.
- Course grade you want
- The overall course percent you want to finish with. For example, 90 is the lowest A on a 90-point scale.
Formula and method
weighted grade = Σ (score × weight) ÷ Σ weight course grade = current grade × (1 − w) + final score × w final score needed = (target − current grade × (1 − w)) ÷ w average needed on ungraded work = (target − weighted grade × W) ÷ (1 − W), W = weight graded so far
In the formulas, Σ means "add up" across all your categories. w is the final exam's weight as a decimal, so 30% is 0.3. W is the total weight of the work graded so far, also as a decimal.
For a weighted grade, each category score is multiplied by its weight. Those results are added up, then divided by the total weight. When the weights add up to 100%, that's your course grade. When they add up to less, dividing by the smaller total gives your grade on the work done so far. It assumes the rest of your work will score at the same level.
For the final exam, the rest of the course carries weight 1 − w. So your current grade adds current × (1 − w) to the course grade. Rearranging that formula gives the final score you need to hit your goal. The letter-grade table repeats the same math with goals of 90, 80, 70 and 60.
When your weights add up to less than 100%, the same rearranging tells you something useful. It shows the average you need on the work not graded yet to finish at each letter.
Worked example
A course counts homework 20%, quizzes 20%, the midterm 25% and the final 35%. The student averages 92, 85, 78 and 88.
- Weighted sum: 92 × 20 + 85 × 20 + 78 × 25 + 88 × 35 = 1,840 + 1,700 + 1,950 + 3,080 = 8,570.
- Total weight: 20 + 20 + 25 + 35 = 100.
- Weighted grade: 8,570 ÷ 100 = 85.70%, a B on a 90/80/70/60 scale.
- Final-exam option: the student has 84% before a final worth 30% and wants 85%. The score needed is (85 − 84 × 0.7) ÷ 0.3 = 26.2 ÷ 0.3 = 87.33%.
- For the letter table: an A (90%) needs (90 − 58.8) ÷ 0.3 = 104%. A B needs 70.67%, a C 37.33% and a D 4%.
- The full range: 0% on the final gives 58.80% for the course, and 100% gives 88.80%.
Result: The weighted course grade is 85.70%. In the final-exam case, the student needs 87.33% on the final to finish with 85%. A B is within reach with 70.67%, while an A would need more than 100%.
Understanding the result
If the score you need is above 100%, the final alone can't get you there unless extra credit is available. If it's zero or below, you'll reach your goal whatever you score.
The results for 0% and 100% on the final show the full range of course grades still possible. That helps you set realistic expectations.
A partial weighted grade, based on less than 100% of the course, can still move a lot as the rest of your work is graded.
Assumptions and limitations
- Each score you enter is already the average percent for its category.
- Weights are percents of the whole course and don't add up to more than 100%.
- In final-exam mode, your current grade covers everything except the final.
- Letter grades use 90% for an A, 80% for a B, 70% for a C and 60% for a D.
- Courses that drop the lowest score, use points instead of weights, or curve grades will work out differently.
- Rounding rules vary. Some teachers round 89.5% up to an A and others don't.
- The letter scale has no plus or minus grades, and may not match your syllabus.
Frequently asked questions
What if my weights don't add up to 100%?
That usually means some work hasn't been graded yet. The calculator divides by the weights you entered, which gives your standing on the graded work so far. Weights that add up to more than 100% aren't accepted, because no single course can have them.
My course uses points instead of percentages. Can I still use this?
Yes. First turn each category into a percent: divide the points you earned by the points possible, then multiply by 100. If the whole course is graded on total points, you don't need weights at all. Your grade is total earned ÷ total possible.
How is the needed final score worked out?
Your current grade fills the part of the course that isn't the final. Subtract its share from your goal, then divide by the final's weight. For example, with 84% before a 30% final and an 85% goal: (85 − 84 × 0.7) ÷ 0.3 = 87.33%.
What do I need on my final to get an A?
Enter your current grade and the final's weight. The table under the answer shows the score needed for 90%, 80%, 70% and 60%. For an A+, or a school where an A starts at 93%, type that number into the goal box instead.
What happens to my grade if I fail the final?
Look at the 0% line. It's your current grade times the share of the course that isn't the final. With 84% going into a 30% final, a zero leaves 58.8%. If you score the same on the final as your current grade, your course grade stays where it is.
Is my grade saved anywhere?
No. The math runs in your browser, and this calculator doesn't create a shareable link with your grades in it.
How this calculator is checked
Method: Weighted arithmetic mean; linear rearrangement for the required final-exam score. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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