What grade do I need on my final exam?
Short answer: take your target, subtract what your current grade already contributes, and divide by the exam's share of the course.
required = (target − current × (1 − exam weight ÷ 100)) ÷ (exam weight ÷ 100)The Final exam mode on the calculator does this in three fields. The useful part is reading the answer properly, and there are three kinds of answer.
You need three numbers
Your current grade, as a percentage, covering everything except the final exam. This is the one people get wrong. If your gradebook shows 83% and that 83% already includes a practice final or a placeholder zero for the exam, it is the wrong input. You want your standing on the graded, non-exam work only.
Your target, the course grade you want. Use a percentage, not a letter — and use your school's actual threshold for that letter. An A starts at 90 in some scales and 93 in others, and the difference changes the answer by several points.
The exam weight, from your syllabus. The percentage of the course grade the final exam carries.
Worked example: current 83%, exam worth 30%
The target you can reach
Target 85%:
required = (85 − 83 × 0.70) ÷ 0.30
= (85 − 58.10) ÷ 0.30
= 26.90 ÷ 0.30
= 89.6666…The calculator shows 89.67% and says: aim for at least 89.67% on the final.
It rounds up, not to nearest. 89.6666… becomes 89.67, because aiming at 89.66 would land you fractionally short of an 85.
The easier target
Target 80%, same current grade and weight:
required = (80 − 58.10) ÷ 0.30 = 21.90 ÷ 0.30 = 73%73%. A five-point drop in your target asked 16.67 fewer points of your exam. That leverage is the whole point of the exam weight, and we come back to it below.
The target that is gone
Target 90%:
required = (90 − 58.10) ÷ 0.30 = 31.90 ÷ 0.30 = 106.3333…The calculator shows 106.33% and labels it Beyond 100%: this target is not reachable without extra credit.
This is worth knowing in week ten rather than in the exam hall. A 90% is no longer available to you through the exam. Perfect marks on the final would put you at 83 × 0.70 + 100 × 0.30 = 88.1%. The honest options now are extra credit, a reweighting your teacher may or may not offer, or a different target.
Note what the number is not: 106.33% is not a score. It is a measurement of how far out of reach the target is.
The target you already have
Current 95%, target 60%, exam worth 20%:
required = (60 − 95 × 0.80) ÷ 0.20 = (60 − 76) ÷ 0.20 = −80The calculator shows −80% and labels it Target secured: you have reached this target even with 0% on the exam, under this formula.
A negative number means the target is locked in by arithmetic alone. Read "under this formula" literally, though: plenty of courses have a separate rule that the exam must be passed, or attended, regardless of your standing. The arithmetic cannot see that rule. Your syllabus can.
What the exam weight actually does
The exam weight is the most important of the three numbers, and the least examined. It decides how much your exam can move your grade — in both directions.
Hold current 83% and target 85%. Change only the weight:
| Exam weight | Score needed | Why |
|---|---|---|
| 10% | 103% | Too little room left to climb 2 points |
| 20% | 93% | Tight |
| 30% | 89.67% | Reachable |
| 50% | 87% | Comfortable |
A light exam protects a good grade and traps a mediocre one. A heavy exam does the opposite: it gives you room to climb, and room to fall. If your exam is worth 50% and you are sitting at 83%, the exam is genuinely the course.
So check the weight in your syllabus before you plan around any of this. A guess at the weight is a guess at the answer.
Five ways this goes wrong
- Your current grade includes the exam. A zero placeholder for an ungraded final drags it down and the required score comes out far too high. Use your non-exam standing.
- Your target is a letter, converted loosely. "An A is 90" is a scale, not a fact. Use your school's published threshold.
- Your course is points-based, not weighted. Then there is no "exam weight" — the exam's points out of the course total are its weight. See why your calculated grade can differ from your gradebook.
- Rounding. If your school rounds 89.5 to 90, a result of 89.67 is comfortable. If it does not, 89.67 means 89.67. Ours does not round up to the next letter; how this calculator works sets out the rule.
- Dropped scores, curves and extra credit. The formula knows none of these. Your syllabus governs.
Next
- How do weighted grades work? — where your "current grade" comes from.
- My weights don't add up to 100% — if your syllabus column is incomplete.
The result is a calculation, not an official grade. Your school's rules decide your grade.
Sources and checks
- Formula, the round-up on the "aim for at least" line, and all three state labels are read from the calculator's code.
- Verified in a browser on 16 October 2026. Current 83%, weight 30%: target 90% → 106.33%, "Beyond 100%"; target 85% → 89.67%, "aim for at least 89.67%"; target 80% → 73%. Current 95%, target 60%, weight 20% → −80%, "Target secured".
- The exam-weight table was produced with the same mode, one weight at a time.
83 × 0.70 + 100 × 0.30 = 88.1%was re-checked in the weighted mode.- Letter-grade thresholds differ between schools; see the two published scales cited on how this calculator works.