What do I need on my final exam?
You can work out the exact score you need on a final exam from three numbers: your grade so far, the grade you want, and how much the final is worth. Here is the formula, three worked examples and what to do when the answer is above 100%.
The short version
- Write down your current grade. Your grade on everything before the final, as a percentage.
- Write down your target. The overall course grade you want, as a percentage.
- Convert the final's weight to a decimal. A final worth 40% is w = 0.40.
- Apply the formula. required = (target − current × (1 − w)) ÷ w.
Skip the arithmetic. The free Final Grade Calculator does this for you, shows the formula and the working with your own numbers, and runs in your browser - nothing you type is uploaded. Also useful: Grade Calculator.
Where the formula comes from
After the final your course grade is a weighted average of two things: what you have now (weight 1 − w) and your final score (weight w).
Example 1: a reachable target
Current grade 80%, final worth 40%, target 85%.
You need 92.5% on the final. The same student needs only (70 − 48) ÷ 0.4 = 55% for a 70 overall, and (80 − 48) ÷ 0.4 = 80% for an 80.
Example 2: more than 100% needed
The same student wants 90%: (90 − 48) ÷ 0.4 = 105%. That is above the maximum score, so 90% cannot be reached from the final alone unless there is extra credit. Knowing this early lets you aim for the best grade that is still possible, or ask about extra credit.
Example 3: a points-based course
Your course has 600 points. 500 points have been graded and you have 412 (82.4%). The final is worth 100 points, so its weight is 100 ÷ 600 = 1/6. For an overall 85%:
Edge cases
- Required score of 0 or less: your target is already secured - even a zero keeps you there.
- Final worth 100%: your current grade no longer matters; the required score equals the target.
- Final worth 0%: it cannot change your grade, so there is nothing to calculate.
The formula also assumes the final is the only graded work left. If other assignments remain, include their weight in the final's share or work out your current grade first.