Final Grade Calculator
The score you need on the final exam.
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Enter the grade you have in the class now, how much your final exam is worth, and the overall grade you're aiming for. The calculator works backwards to tell you the exact score you need on the final — and warns you if the target is already locked in or out of reach.
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What Do I Need on the Final? — The Quick Answer
Your final grade is your current grade for the non-final portion plus your final score for the final's share. Rearranging that: the score you need equals your target, minus what your current grade already contributes, divided by the final's weight.
Shortcut
needed = (target − current × (1 − weight)) ÷ weight (weight as a decimal)
Current 85%, want 80% overall
| Final is worth | You need | Why |
|---|---|---|
| 20% | 60.0% | most of the grade is locked in |
| 30% | 68.3% | worked example below |
| 50% | 75.0% | the final carries more weight |
If the number comes out above 100%, your target can't be reached with the final alone. If it comes out at zero or below, you've already secured your target no matter how the final goes.
How It Works
The Formula
Solving the weighted grade for the final score
Formula
overall = current × (1 − w) + final × w → final = (overall − current × (1 − w)) ÷ w (w = final's weight as a decimal, e.g. 30% → 0.30)
Variables
What you've already earned
Your current grade only counts for the part of the course that isn't the final. If the final is 30% of the grade, your current work is the other 70%, so it contributes current × 0.70 to the overall.
What the final adds
The final exam contributes its score times its weight. Rearranging the overall-grade equation isolates this term and solves for the final score you need.
Note: The same formula works for any single remaining assessment, not just an exam — a final project, presentation, or paper. Just enter its weight.
Worked Example
Current 85%, final worth 30%, want 80% overall
What your current grade contributes
The non-final portion is 70% of the grade: 85 × 0.70 = 59.5.
What the final must contribute
You need 80 overall, so the final must supply 80 − 59.5 = 20.5 of the total.
Convert to a final score
The final is worth 0.30, so divide: 20.5 ÷ 0.30 = 68.3%.
Check
85 × 0.70 + 68.3 × 0.30 = 59.5 + 20.5 = 80%. Correct.
Reference Guide
| unit | value | note |
|---|---|---|
| Final worth 20% | 60.0% | need on final |
| Final worth 30% | 68.3% | need on final |
| Final worth 50% | 75.0% | need on final |
Key Features
Last updated: October 5, 2026
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Frequently Asked Questions
How do I calculate what I need on my final exam?
Take the grade you want overall, subtract what your current grade contributes (your current grade times the portion of the course that isn't the final), then divide by the final's weight. For a current 85%, a final worth 30%, and an 80% target: (80 − 85 × 0.70) ÷ 0.30 = 68.3%.
What does it mean if the calculator says I need over 100%?
It means your target grade can't be reached with the final alone — even a perfect score wouldn't be enough. You'd either need to lower your target, or earn extra credit if your course offers it. The calculator flags this so you don't bank on an impossible result.
What if it says I need 0% or less?
Your desired grade is already locked in. Your current grade is high enough (and the final's weight low enough) that you'd stay at or above your target even if you scored zero on the final. You can't fully relax — but the pressure's off.
What should I enter as my 'current grade'?
Enter your current overall average in the class — the grade you'd finish with if the final weren't counted. If your syllabus lists category weights (homework, quizzes, midterms), use the Weighted Grade Calculator first to find that current average, then bring it here.