Grade Calculator
Work out your weighted class grade and find the score you need on the final exam to reach a target, including when that target is out of reach.
Current grade · total weight 0%
Score needed on the final exam
Nothing in the formula caps the answer at 100
If your work so far averages C and the final is worth W of the grade, the
score F you need for an overall T is
F = (T − C × (1 − W)) ÷ W. That is a straight line with no ceiling on it, so
it will happily return a number you cannot score. The values this page starts with —
85% going in, a final worth 30% — are already one
of those cases:
| Target | Needed on the final | |
|---|---|---|
| A (90% overall) | 101.7% | out of reach — a perfect final still falls short |
| B (80% overall) | 68.3% | reachable |
| C (70% overall) | 35.0% | reachable |
| D (60% overall) | 1.7% | reachable |
An A needs 101.7%, which is not a hard exam — it is an impossible one. It was gone before the paper was written. At the other end, a D needs 1.7%, which means you could hand in a nearly blank sheet and still hold it. Both ends matter, and a calculator that prints the bare number leaves you to notice which one you are looking at.
The weight decides more than the mark does
How far your grade can still move is set entirely by what the final is worth — and, unusually for a number on a page like this, it does not depend on your current average at all. A final worth W can shift your overall grade by exactly W, no more:
| Final worth | At 75%, you finish between | Swing | Needed for a B |
|---|---|---|---|
| 10% | 67.5% and 77.5% | 10 points | out of reach |
| 20% | 60.0% and 80.0% | 20 points | 100.0% |
| 30% | 52.5% and 82.5% | 30 points | 91.7% |
| 40% | 45.0% and 85.0% | 40 points | 87.5% |
| 50% | 37.5% and 87.5% | 50 points | 85.0% |
A 10% final cannot rescue a failing grade and cannot sink a passing one — it is worth about a tenth of the anxiety it attracts. A 50% final means the whole semester so far counts for exactly as much as one afternoon. And even that has limits: sitting on 70% with half the grade still to play for, a perfect final gets you to 85%, so an A is already gone.
Where each grade stops being winnable
Setting the required score to exactly 100% and solving backwards gives the lowest average you can walk into the final with and still, in principle, get there:
| Grade | Final worth 10% | Final worth 30% | Final worth 50% |
|---|---|---|---|
| A (90%) | 88.9% | 85.7% | 80.0% |
| B (80%) | 77.8% | 71.4% | 60.0% |
| C (70%) | 66.7% | 57.1% | 40.0% |
| D (60%) | 55.6% | 42.9% | 20.0% |
With a final worth only 10%, an A requires you to already be at 88.9% — the exam can add at most nine tenths of a point to the gap. With a final worth half the grade, 80.0% is enough. Heavier finals are more forgiving of a bad semester and more dangerous to a good one, which is the same fact seen from either side.
How to use
- Enter each category with its weight and your score.
- Read your current weighted grade.
- Enter a target to see what the final must be.
- Note when the required score exceeds 100.
Frequently asked questions
How is a weighted grade calculated?
Each category's score is multiplied by its weight, and the results are summed. If homework is worth 20 per cent and you scored 90, it contributes 18 points to the final total. The weights should sum to 100 per cent — if they do not, the syllabus is worth rereading.
What score do I need on the final?
Rearranging the same arithmetic: subtract what you have already earned from the target, then divide by the final's weight. The result is sometimes above 100, which is the calculator telling you the target is unreachable — worth knowing early rather than after the exam.
Why does the final exam matter so much?
Because its weight is usually large relative to any single earlier assignment. A final worth 30 per cent can move a grade by several letter grades on its own, which cuts both ways — it is also the largest single opportunity to recover.
What if some categories are not graded yet?
Then your current grade is computed only over completed work, which is what most gradebooks show. It represents your standing so far rather than a prediction, and it can shift substantially once a heavily weighted item is added.
How do dropped scores work?
Many courses drop the lowest score in a category, which changes the arithmetic — your effective average is over fewer items. Whether the drop is applied before or after weighting varies, so the syllabus is the authority.
Are extra credit points included?
They usually add to the numerator without increasing the denominator, which is why extra credit can push a category above 100 per cent. Some systems cap it. The effect on the final grade depends entirely on the category's weight.
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