What do I need on my final?
Your final exam can only move your grade as far as its weight allows. Everything you have done so far is locked in and counts for the rest of the course. So the question comes down to one gap: how much the final has to add on top of what you already have to reach your target.
That gives one formula, with the weight written as a decimal (25% is 0.25):
score needed = (target − current × (1 − weight)) ÷ weight
With 84% going in, a final worth 25% and a B (80%) as the goal: the work so far is worth 84 × 0.75 = 63 points of the course grade. You need 80, so the final has to supply 17, and 17 ÷ 0.25 = 68. A 68% on the final gets you the B.
Using the calculator
- Current grade: your percentage in the class right now, before the final. Most online gradebooks show it. If yours has already entered the final as a 0, see the mistakes section below.
- Final exam weight: the share of the course grade the final is worth, from your syllabus. Type 25 for 25%, not 0.25.
- Course grade you want: any percentage, or tap A, B, C or D to fill in the common cut-offs.
- Points (optional): if the final is marked out of, say, 150 points, enter that and the result also shows the points you need — 68% of 150 is 102 points.
Alongside the main answer you get two tables. One lists what the final needs to be for an A, B, C and D, so you can see the next grade up and the one you must not drop below. The other runs through final scores from 0 to 100 and shows the course grade each one would give you, with the first score that reaches your target highlighted.
Reading the answer
The score you need is rounded up to two decimals, never to the nearest. If the exact answer is 99.333…%, the calculator shows 99.34%, because 99.33% would leave you a sliver below the target. The exact figure is in the working underneath.
When the answer is 90% or more, the calculator marks it as reachable but tight. It is still worth knowing: it tells you that going into the exam, a B-level performance will not be enough.
Worked examples
A comfortable target
Maya has 84%, her final is worth 25% and she wants a B. She needs 68% on the final — below her current average, so she can aim for a B without a perfect exam.
A target that needs a near-perfect final
Jordan has 86%, the final is worth 30%, and the goal is an A (90%). The work so far contributes 86 × 0.7 = 60.2, so the final has to supply 29.8, and 29.8 ÷ 0.3 = 99.333…%. The calculator shows 99.34%. It is technically possible, but it is a good moment to check whether any other work can still be improved.
A target that is already safe
Sam has 95%, the final is worth 20%, and a scholarship only requires 75% in the course. The formula gives −5% for the final. That is not a score to aim for; it means the target is already secure — a 0 on the final would still leave 95 × 0.8 = 76%. The calculator says so instead of printing −5%. An A would still take 70% on the final.
A target that cannot be reached
Priya has 72%, her final is worth 15%, and she was hoping for a B. That would need about 125.33% on the final. Even a perfect final brings her only to 72 × 0.85 + 15 = 76.2%, a C. The calculator shows that best possible grade and does not treat 125.33% as a score to aim for.
The same student, different weights
With 80% now and a target of 85%, the weight of the final changes everything:
| Final exam weight | Score needed |
|---|---|
| 20% | 105% — out of reach |
| 40% | 92.5% |
| 50% | 90% |
A heavily weighted final is good news when you are behind and bad news when you are ahead: it gives you more room to catch up, and more room to fall.
Percentages, decimals and points
The calculator takes percentages: 25 means 25%. Syllabi write the same thing in different ways — “0.25”, “25%” or “one quarter of the grade”. If the course is graded in points, divide the final’s points by the total: a 200-point final in a 1,000-point course is worth 20%.
Watch for a final that is weighted inside a category. If exams are 50% of the course and the final is half of the exam category, the final is worth 25% of the course, not 50%.
Mistakes that give the wrong answer
- A gradebook that already counts the final as 0. Some systems include the final before you take it. With 84% on the work so far and a final worth 20%, the gradebook shows 67.2%. Enter 84, not 67.2, or the answer will be far too high.
- Other work still to come. The formula assumes the final is the only thing left. If a project or lab is still outstanding, add its weight to the final’s and read the answer as the average you need across both.
- Typing the weight as a decimal. 0.25 here means a quarter of one percent, which makes the final almost irrelevant. Type 25.
- Assuming your school rounds up. An 89.5% course grade is an A at some schools and a B at others. If you are close to a boundary, aim for the target itself, not the rounding.
Edge cases
- Final worth 0%. If the weight is 0, the final cannot change the course grade at all. The calculator says so directly — either the target is already met, or it never can be — rather than dividing by zero.
- Final worth 100%. The current grade drops out entirely and the score needed on the final equals the target itself.
- A weight above 100 or a negative number anywhere. Current grade, weight and target must each be 0 or more, and the weight cannot exceed 100, since a single item cannot be worth more than the whole course. The form rejects these rather than returning a number that means nothing.
- A current grade above 100. Allowed, for a course that has already given extra credit — the arithmetic treats it as entered.
When your real grade may differ
The result is exact for the numbers you enter, but courses are not always graded by one simple weighted average. Dropped lowest scores, a final that replaces your weakest test, curves, extra credit, plus/minus letter scales and minimum-score rules (some courses require passing the final itself) all change the outcome. Your syllabus has the rules that apply; when in doubt, ask your instructor.
To work out the grade you have now from individual assignments and category weights, use the grade calculator, then bring that figure back here. If your school marks on a whole-number points scale instead of percentages, the grade average calculator is built for that system.
Frequently asked questions
How do I work out what I need on my final?
Subtract what your current grade already contributes from the grade you want, then divide by the final’s weight. As a formula: needed = (target − current × (1 − weight)) ÷ weight, with the weight as a decimal. With 84% now, a final worth 25% and a target of 80%, that is (80 − 84 × 0.75) ÷ 0.25 = 68%.
Where do I find how much my final is worth?
In the syllabus or course outline, usually in a grading breakdown such as “Final exam 25%”. If the course is graded in points, divide the final’s points by the course total: a 200-point final in a 1,000-point course is worth 20%.
What if I have more than one thing left, not just the final?
If you expect to score about the same on everything that is left, add their weights together and treat them as one “final”. A project worth 10% and an exam worth 20% become a 30% block, and the answer is the average you need across both. If they are very different, work out each category with the grade calculator instead.
Why is the score rounded up?
Because rounding down could leave you just short. If the exact answer is 90.583…%, a 90.58% on the final would give a course grade a fraction below the target. The calculator shows the exact value in the working and rounds the headline figure up to two decimals.
What does it mean if the answer is over 100% or below 0%?
Over 100% means the target cannot be reached with the final alone, even with a perfect score; the calculator shows the best course grade still possible instead. Below 0% means the target is already safe — even a 0 on the final would leave you at or above it. Neither is shown as a score to aim for.
Will my teacher’s gradebook give exactly the same result?
Only if your course works the way this formula assumes: one current grade covering everything except the final, and a fixed weight for the final. Dropped scores, a final that replaces your lowest test, curves and your school’s rounding and letter cut-offs can all move the real grade. Check the syllabus for those rules.