What you need on the final — or your overall grade from weighted parts
Enter a grade (0-100)
Enter a target (0-100)
Enter a weight (1-100)
The last few weeks of every course revolve around one piece of arithmetic: with the final exam worth X% of the grade, what score does it take to end at a target? Guessing wrong in either direction is costly — studying in panic for a score you never needed, or relaxing through a final you actually had to win. This calculator does the algebra instantly, in two directions.
Score-needed mode takes your current average, the weight of the final, and the overall grade you want, and returns the exact score required — or tells you when the target is mathematically out of reach. Overall mode combines two graded components by weight into your running overall, for courses structured as quarters, midterms or parts.
The logic behind the first line: your current grade already fills (1 − w) of the course, so it contributes current × (1 − w) to the final total. Whatever the target needs beyond that must come from the final — divided by how much of the total the final controls.
You are at 82% and the final is worth 30%. To finish at 85%: needed = (85 − 82 × 0.70) ÷ 0.30 = (85 − 57.4) ÷ 0.30 = 92. To finish at 80%: (80 − 57.4) ÷ 0.30 = 75.3 — comfortably below your current level. The same course, two very different study plans.
| Current | Final weight | Target | Needed on final |
|---|---|---|---|
| 82% | 30% | 80% | 75.3% |
| 82% | 30% | 85% | 92% |
| 82% | 30% | 90% | 108.7% — impossible |
| 70% | 50% | 80% | 90% |
Always check your syllabus for the exact weights — courses differ on whether the final replaces or merely adds to prior work, and that detail changes everything.
每门课的最后几周都绕着同一道算术题转：期末占总评 X%，要达到目标总评得考多少分？两头猜错的代价都很大——为根本不需要的分数恐慌式突击，或者在实际必须拿下的大考松懈。这个计算器把代数一步算完，而且是双向的。
「期末需要多少分」模式：输入当前平均分、期末占比和目标总评，直接给出所需分数——当目标在数学上已不可达时也会明说。「两部分合成总评」模式：按权重合并两个已评部分（ quarters、期中、分册的课程都适用），得到当前总评。
第一行的逻辑：当前成绩已经填满了课程的 (1 − w) 部分，它对总评的贡献是「当前 × (1 − w)」。目标总评超出这个贡献的部分，必须由期末提供——再除以期末在总评中的控制权大小。
你目前 82 分，期末占 30%。想总评达到 85 分：所需 = (85 − 82 × 0.70) ÷ 0.30 = (85 − 57.4) ÷ 0.30 = 92 分。想保住 80 分： (80 − 57.4) ÷ 0.30 = 75.3 分——低于你现有水平，轻装上阵即可。同一门课，两套完全不同的复习策略。
| 当前 | 期末占比 | 目标 | 期末所需 |
|---|---|---|---|
| 82 分 | 30% | 80 分 | 75.3 分 |
| 82 分 | 30% | 85 分 | 92 分 |
| 82 分 | 30% | 90 分 | 108.7 分——不可能 |
| 70 分 | 50% | 80 分 | 90 分 |
务必核对课程大纲里的准确占比——有的课程期末是「替换」此前成绩而不只是「叠加」，这个细节会改变一切。
Use: needed = (target grade − current grade × (1 − final weight)) ÷ final weight. Example: an 82% average with a final worth 30% of the course, targeting 90%: (90 − 82 × 0.70) ÷ 0.30 = (90 − 57.4) ÷ 0.30 = 108.7 — above 100, so 90% is out of reach.
Each component is multiplied by its weight and the results are added: overall = grade₁ × weight₁ + grade₂ × weight₂. The two-part mode here normalises the weights, so 80% at 40% weight plus 70% at 60% weight gives (80×40 + 70×60) ÷ 100 = 74%.
Combine the graded components first: multiply each completed item by its weight, add them, then divide by the total weight covered. That combined figure becomes your "current grade", and the remaining weight belongs to the final. Then use the score-needed mode as usual.
Last reviewed: October 5, 2026 · How we calculate · Sources: Standard weighted-average grading
最近复核：2026 年 10 月 5 日 · 我们的计算方法 · 来源：标准加权平均评分法