Education guide
What Grade Do I Need on My Final? The Formula, Explained
Work out the exact final exam score you need for the grade you want, with worked examples, weighted and points-based classes, and syllabus rules that change the answer.
By M2Toolkit Editorial TeamPublished 6 min read
Quick answer
Score needed on the final = (grade you want − current grade × (1 − final weight)) ÷ final weight, with the weight as a decimal.
If you have an 82% now, want an 85% overall, and the final is worth 30%: (85 − 82 × 0.7) ÷ 0.3 = (85 − 57.4) ÷ 0.3 = 92%. If the answer comes out above 100%, that target is out of reach through the exam alone. If it's below zero, you've already locked it in.
Knowing the exact number takes a lot of the guesswork out of exam season. Sometimes it's good news (you need a 65% to keep your B); sometimes it's a reality check (no score will get you an A, so protect the B+ instead). Either way, it tells you where to spend your revision time. Here's how to work it out, the things that trip the calculation up, and what the numbers look like for common situations.
Working it out by hand
- 1Find your current grade — your average on everything graded so far, as a percentage.
- 2Find the weight of the final from your syllabus, and write it as a decimal (25% = 0.25).
- 3Multiply your current grade by (1 − final weight). That's how many points of your overall grade are already banked.
- 4Subtract that from your target grade. What's left has to come from the final.
- 5Divide by the final weight.
Worked example: current grade 78%, final worth 20%, target 80%. Banked points: 78 × 0.8 = 62.4. Still needed: 80 − 62.4 = 17.6. Divide by 0.2: 88% on the final.
Try the free Final Exam Grade CalculatorEnter your current grade, your target and the weight of the final. It shows the score you need and what overall grade you'd end up with at 60%, 70%, 80%, 90% and 100%.What you need with an 85% going in
The weight of the final changes everything. With the same 85% average, here's the score needed for each target:
| Final is worth | To keep a C− (70%) | To keep a B− (80%) | To reach an A− (90%) |
|---|---|---|---|
| 15% | Already secured | 51.7% | Not possible (118.3%) |
| 20% | 10% | 60% | Not possible (110%) |
| 25% | 25% | 65% | Not possible (105%) |
| 30% | 35% | 68.3% | Not possible (101.7%) |
| 40% | 47.5% | 72.5% | 97.5% |
| 50% | 55% | 75% | 95% |
Two things stand out. A light final can't move you very far in either direction — with a 20% final, an 85% student can't reach 90% but also can't realistically fall below a C. A heavy final cuts both ways: it's the only route to an A here, and also the only way to lose the B.
Getting your current grade right
Most wrong answers come from a wrong input, not a wrong formula. Before you trust the number, check these:
- Use the grade on completed work only. Some online gradebooks count missing or not-yet-graded assignments as zero until they're marked, which drags the displayed average down. Others ignore them. Make sure you know which yours does.
- Weighted categories. If homework is 20%, quizzes 30%, the midterm 20% and the final 30%, your current grade is the weighted average of the first three, rescaled to 70%. With 92% homework, 78% quizzes and 81% on the midterm, that's (0.2 × 92 + 0.3 × 78 + 0.2 × 81) ÷ 0.7 = 82.9%. To finish with an 85%, you'd need exactly 90% on the final. The Weighted Grade Calculator does the category maths for you.
- Points-based classes. If your course is graded out of total points rather than percentages, skip the formula. Subtract the points you have from the points you need for your target, then divide by the points the final is worth. With 640 of 700 points so far, a 300-point final and a target of 900 out of 1,000, you need 260 ÷ 300 = 86.7%.
Syllabus rules that change the answer
Plenty of courses have a twist that the basic formula doesn't know about. Read the grading section of your syllabus for any of these:
- The final replaces your lowest test score if it's higher. A strong final then helps twice.
- You must pass the final to pass the course, regardless of your average. Your required score is then at least the exam pass mark.
- Lowest quiz or homework dropped. This raises your current grade before the final.
- Curved or scaled exams. Your raw score may be adjusted after everyone sits the exam, so the number you need is an estimate.
- Rounding. Some instructors round 89.5% to 90%; some don't. Don't plan on it, but it's worth knowing.
What's the lowest score I can get and still pass?
Use the same formula with the pass mark as your target. With 72% going in, a final worth 25% and a pass mark of 60%: (60 − 72 × 0.75) ÷ 0.25 = (60 − 54) ÷ 0.25 = 24%.
That's a comforting number, but only if your course doesn't require a minimum score on the final itself. Many do, which is the rule above that people most often miss.
When the number is over 100%
It's frustrating, but it's useful to know now rather than after results day. A few honest options:
- Ask whether there's any remaining extra credit, a resubmission, or an assignment still to be graded.
- Set the next grade down as your target and recalculate. Moving from a B+ to a B often feels less important than it is — but it's much better than a B−.
- Look at the effect on your GPA. One grade step in one course moves a semester GPA less than most people expect; the GPA Calculator shows exactly how much.
Turning the number into a revision plan
Once you know you need, say, 88%, look back at your past tests in the course and see where you lost marks. That tells you which topics to spend most of your time on. Count the days you have left and divide the topics across them — the Exam Countdown and Daily Study Planner help with that. If you score a practice paper, the test score to percentage charts make it quick to see where you are.
Frequently asked questions
How do I calculate what I need on my final?
Subtract your current grade multiplied by (1 − the final's weight) from the grade you want, then divide by the final's weight. With 82% now, a target of 85% and a 30% final: (85 − 82 × 0.7) ÷ 0.3 = 92%.
What does it mean if I need more than 100% on my final?
The target can't be reached through the final exam alone. Choose a lower target, or ask your instructor whether extra credit or regrading is available.
Can my final exam lower my grade?
Yes. If you score below your current average on the final, your overall grade drops. The heavier the final is weighted, the further it can pull your grade in either direction.
What if my final is worth 50%?
Then the final counts as much as everything else combined. The score you need is simply 2 × target − current. With 78% now and a target of 80%, you need 82%.
Does the calculator work for points-based classes?
Convert to percentages first: your current grade is the points you've earned divided by the points available so far, and the final's weight is its points divided by the course total. Or subtract the points you have from the points you need and divide by the final's points.