What-If Grade Calculator
This is the forward question: if the final goes this way, what is my grade? The final grade calculator answers the reverse one.
The forward question
The final grade calculator answers "what do I need?" This page answers the other direction: "if the final goes like this, where do I land?" Both are useful, and students usually need this one first — it tells you whether the exam is a threat or a formality.
Final grade = current × (1 − w) + expected × w, where w = final weight ÷ 100
Everything already graded is locked in at current × (1 − w). The final supplies the remaining w of the course.
What each outcome is worth
Current grade 84%, final worth 25% of the course:
| Score on final | Locked in (63.0) | Course grade | Effect |
|---|---|---|---|
| 0% | 63.0 | 63.0 | Worst case |
| 60% | 63.0 | 78.0 | Drops you to a C+ |
| 70% | 63.0 | 80.5 | B− range |
| 80% | 63.0 | 83.0 | Holds your B |
| 90% | 63.0 | 85.5 | Near your average |
| 100% | 63.0 | 88.0 | Best case |
The spread between the worst and best case is 25 points — the weight of the final. That is the real meaning of "the final is worth 25%": no exam performance can move you more than 25 points in either direction, and no amount of prior work can protect you from a zero.
When the weight is heavier
The same 84% with a final worth 40% behaves very differently: a 70 on the exam gives 78.4%, and a 100 gives 90.4%. The locked-in portion shrinks to 50.4 and the exam's leverage grows to 40 points. Course design, not effort, decides how much the last day matters.
Where this model breaks
- A curve. If the instructor curves the final, the raw percentage you enter is not the percentage that gets recorded.
- Extra credit. Added on top of the total, not inside the weighted average — enter the score you expect including it.
- Replacement policies. Some syllabi drop the lowest exam or let the final replace a midterm. That is a different formula, and the model here will be wrong in your favour or against it.
- Rounding at a boundary. 89.5 is sometimes recorded as an A− and sometimes as a B+. Ask before the exam, not after.
Common questions
Why does a 100 on the final only get me to 88%?
Because 75% of the course is already fixed at 84%, which contributes 63 points. The final can add at most its own 25 points, and 63 + 25 = 88. A perfect exam cannot undo a term's worth of 84s — that is arithmetic, not pessimism.
Should I enter my current grade or my last exam grade?
The running course grade — the number your gradebook shows as the overall standing, not the score on the most recent test. If the gradebook only shows points, divide points earned by points possible first.
What if I do not know the final's weight?
Look at the syllabus; it is usually stated in the grading breakdown. If the syllabus lists categories rather than the final, add up everything the final replaces. A guess of 20–30% is common for a single exam, but guessing here changes the answer a lot, so it is worth finding the real number.
How do I turn this into a target instead?
Use the final grade calculator: enter the grade you want and it returns the score the final has to deliver, including the honest cases where the answer comes out above 100%.