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Start with the syllabus weights
Consider a course with homework worth 30%, a midterm worth 40%, and a final exam worth 30%. Your homework average is 90% and your midterm score is 80%; the final has not been graded. This example assumes these three categories make up the whole course and that no score is dropped, replaced, curved, or given extra credit.
Homework has contributed 90 × 0.30 = 27 points toward the final course percentage. The midterm has contributed 80 × 0.40 = 32 points. You have earned 59 course percentage points from the 70% of the course completed so far. The remaining 30 points depend on the final.
| Category | Course weight | Score | Course points earned |
|---|---|---|---|
| Homework | 30% | 90% | 27 |
| Midterm | 40% | 80% | 32 |
| Final exam | 30% | Ungraded | Not yet earned |
Why the current average is 84.29%, not 59%
The completed-work average is 59 ÷ 0.70 = 84.2857%. It describes performance on the work already graded. The 59 figure instead measures points earned toward the entire course. Both are useful, but they answer different questions.
In Category weights & what-if grades, enter Homework with weight 30 and score 90, Midterm with weight 40 and score 80, and Final exam with weight 30 and a blank score. A blank means ungraded; zero means an actual scored zero. Clear any example what-if value if you only want to inspect completed work.
Do not enter 59 as Current grade in the final-exam calculator. That field expects the average on completed work. Using 59 would count the unfinished final against you twice. Keep the unrounded 84.2857142857 value when transferring this example; rounding it to 84.29 slightly changes the required score.
Solve for the score you need
To finish with 85%, the final must contribute another 85 − 59 = 26 course points. Because the exam is worth 30%, its required score is 26 ÷ 0.30 = 86.6667%. Check the answer by substitution: 59 + 0.30 × 86.6667 is approximately 85.
In general, required final score = [target − current average × (1 − final share)] ÷ final share. Enter a current average of 84.2857142857, a target of 85, and a final weight of 30 in Required final score. The calculator uses the percentage weight as a fraction internally.
| Target course grade | Required final score | Interpretation |
|---|---|---|
| 80% | 70% | 21 additional course points |
| 85% | 86.67% | 26 additional course points |
| 90% | 103.33% | Exceeds a 100% exam maximum |
An impossible target is useful information
With 59 course points already earned, a perfect final adds 30, producing a maximum overall grade of 89%. A 90% target therefore needs more than a perfect final under this model. That result is not a prediction of failure; it identifies a limit in the weights and scores you supplied.
Check whether the syllabus has a replacement exam, dropped assessment, extra-credit provision, or a different final weight. If it does, model the actual rule before relying on the result. The calculator cannot infer an instructor’s policy or promise that a rounded score will cross a grade boundary.
Measure how much the final can move your grade
Every extra point on a final worth 30% adds 0.30 points to the course grade. Increasing the exam score from 80% to 90% raises the overall grade from 83% to 86%. This gives a practical scale for judging how much a change in exam performance can affect the outcome.
The same ten-point exam improvement would move a course grade by only one point if the exam were worth 10%. Always compare scenarios using the same course weights; changing both the exam score and its weight makes it harder to tell what caused the difference.
Know when this worksheet does not apply
A points-based course uses total earned points divided by total possible points. It does not necessarily assign equal importance to category percentages. Use the Earned and possible points mode for that system. If a gradebook already includes missing work as zeros, reconstruct the completed-work average before using it to solve for an unfinished final.
These are numerical examples, not school grading rules. The weighted-mean reference below explains the arithmetic. Your syllabus and instructor determine category weights, letter cutoffs, rounding, and treatment of missing work.