# Final grade calculator

Canonical: https://duckyhelper.com/tools/final-grade-calculator/
Updated: 2026-10-01

Enter your grade now, how much the final counts and the grade you want. You need (goal minus current grade times the rest of the weight) divided by the final's weight. Example: at 84% with a final worth 25%, an 85% overall needs 88% on the final. Over 100% means the goal is not reachable.

## The final grade formula

Your final grade is a mix of two parts: the grade you have now, which counts for everything except the final, and the final exam itself. Write the final's weight as a decimal \(w\) (25% is 0.25), your grade now as \(C\) and the grade you want as \(G\).

$$
\text{needed on final} = \frac{G - C\,(1 - w)}{w}
$$

The reverse, "what if I get \(F\) on the final", is the same mix written forward:

$$
\text{grade after final} = C\,(1 - w) + F\,w
$$

## Worked examples

**Example 1: the score you need**

Problem: You have 84% in the class. The final is worth 25%. What do you need on the final to finish with 85%?

1. Everything except the final counts for \(1 - 0.25 = 0.75\) of the grade. Your current grade fills that part.

   $$
   84 \times 0.75 = 63
   $$
2. Subtract that from the goal to see what the final has to bring in.

   $$
   85 - 63 = 22
   $$
3. Divide by the final's weight.

   $$
   \frac{22}{0.25} = 88
   $$

Answer: 88% on the final

**Example 2: when the goal is out of reach**

Problem: You have 70%. The final is worth 20%. Can you still finish with 90%?

1. Apply the formula.

   $$
   \frac{90 - 70 \times 0.8}{0.2} = \frac{90 - 56}{0.2} = 170
   $$
2. 170% is more than a perfect score, so 90% is not reachable without extra credit.
3. The best you can do is 100% on the final.

   $$
   70 \times 0.8 + 100 \times 0.2 = 76
   $$

Answer: Not reachable: the most you can finish with is 76%

> **Tip: Use the grade before the final**
>
> "Grade now" means your class grade without the final, the way your gradebook shows it today. If your class uses weighted categories, work it out first with the [grade calculator](https://duckyhelper.com/tools/grade-calculator/).

## Points-based classes

If your teacher adds up points instead of weighting categories, the final's weight is its points divided by all the points in the class. A 200 point final in a class worth 1,000 points in total has a weight of 20%.

## Frequently asked questions

### What does it mean if I need more than 100%?

It means no score on the final can bring you to that goal, unless the final has extra credit. The calculator shows the best grade you can still finish with, which is what a perfect 100% would give you. Try a lower goal, like the next letter grade.

### What if the answer is 0% or less?

Then you already have the grade you want, even with a 0 on the final. The calculator says "any score" and shows what a 0 would leave you at. It is still worth doing well: the final may count toward other things, like a course placement.

### How do I find my final exam's weight?

Check the syllabus or the grading section of your class website. It is often given as a percent, such as "Final exam: 20%". In a points-based class, divide the final's points by the total points for the term.

### Can I see what grade I get with a certain score?

Yes. Switch to "What if I get" and enter a score for the final. The calculator shows your grade after the final using grade now times the rest of the weight, plus the final's score times its weight.

### Why is my answer different from my teacher's?

Teachers sometimes round grades, drop the lowest quiz, or count the final inside a category instead of on its own. If the final sits inside an exams category, its real weight is the category weight times its share of that category.

## Related

- [Grade calculator](https://duckyhelper.com/tools/grade-calculator/)
- [GPA calculator](https://duckyhelper.com/tools/gpa-calculator/)
- [Pomodoro study timer](https://duckyhelper.com/tools/study-timer/)

## Try asking Ducky

- "I need an 88 on my chemistry final. Make me a study plan for the next 5 days."
- "Quiz me on everything that will be on my algebra final."
- "Explain the three topics I keep getting wrong on practice tests."

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