Final Grade Calculator
Enter your current grade, how much of the course it covers, the grade you want and how much the final is worth. The calculator solves for the score you need on the final, and says plainly if the target is already secured or out of reach.
Answer
Score needed on the final
92%
Scoring 92 on the final brings the course to 85.
- weighted points needed
- 8,500
- points already earned
- 5,740
- total weight
- 100%
Check the work
Every line comes from the same calculation as the answer.
needed = (target × total weight − current × weight so far) ÷ final weight
| needed | 85 × 100 | 8,500 |
|---|---|---|
| earned | 82 × 70 | 5,740 |
| final score | (8,500 − 5,740) ÷ 30 | 92 |
How it works
Your course grade will be a weighted average of the work done so far and the final. If you know three parts of that average — your current grade, the weights and your target — the fourth, the final score, follows from rearranging it.
With a current grade of 82 on 70% of the course and a final worth 30%, reaching 85 overall needs (85 × 100 − 82 × 70) ÷ 30 = 92 on the final. The same arithmetic shows how a heavier final gives more room to recover, and a lighter one less.
Sometimes the answer is below zero, which means the target is reached whatever happens on the final, or above 100, which means it cannot be reached on a 100-point final. The calculator reports both cases in words rather than leaving you with a puzzling number.
Formula
needed = (target × (weight so far + final weight) − current × weight so far) ÷ final weight
The target grade times the total weight is the number of weighted points needed; subtracting the points already earned leaves the points the final must supply.
Worked examples
- Try these numbers
Current 82 on 70%, aiming for 85, final worth 30%
- 85 × 100 = 8,500 weighted points needed.
- 82 × 70 = 5,740 already earned.
- (8,500 − 5,740) ÷ 30 = 92.
You need 92 on the final.
- Try these numbers
A target already secured
- 70 × 100 = 7,000 points needed; 95 × 80 = 7,600 already earned.
- (7,000 − 7,600) ÷ 20 = −30.
The score needed is −30, so any score on the final keeps you at 70 or above.
- Try these numbers
A target out of reach
- 80 × 100 = 8,000 needed; 60 × 75 = 4,500 earned.
- (8,000 − 4,500) ÷ 25 = 140.
140 is above 100, so 80 cannot be reached with this final alone.
Inputs and results
- Current grade
- Your weighted average on the work marked so far, as a percentage.
- Weight so far
- How much of the course grade the marked work covers, as a percentage.
- Target grade
- The overall grade you want, as a percentage.
- Final weight
- How much the final counts towards the course grade, as a percentage.
- Score needed
- The score on the final that makes the weighted average equal the target.
When to use it
- Planning revision by knowing the score that secures a target grade.
- Checking whether a grade boundary, such as a B or a pass mark, is still reachable.
- Seeing how much the final exam’s weight changes the score you need.
Common mistakes
- Using the plain average of past scores as the current grade instead of the weighted average shown in the grade portal.
- Entering weights that add up to more than 100 because the final was counted twice.
- Reading a negative result as an error: it means the target is already secured.
What it does not do
- It assumes the final is the only assessment left; if other work remains, include it in the final’s weight or use the grade calculator.
- It does not apply curves, minimum-score rules for passing the exam itself, or rounding of the final grade.
- It works on one scale, usually percentages; letter grades need converting to their percentage boundaries first.
Method and assumptions
The course grade is modelled as the weighted average of the current grade and the final score. Setting that average equal to the target and solving for the final score gives the formula above.
The weights are used as entered and need not total 100; the calculation uses their sum as the total weight.
Assumptions
- The current grade is already a weighted average.
- The final is the only remaining assessment.
Edge cases
- A final weight of zero is refused, because nothing could change the grade.
- A result below 0 means the target is already secured.
- A result above 100 means the target cannot be reached on a 100-point final.
Sources and corrections
This calculator uses an elementary formula, so it needs no outside data source. The method, the rounding rules and how a reported error is corrected are set out in the site standards.
Result looks wrong?
Send the inputs you used and the answer you expected. Every report is checked against the formula and its tests, and confirmed errors are corrected in public.