How the final exam math works
If the final is worth 25% of your grade, everything you've done so far is worth the other 75%. Your class grade will be 75% of your current grade plus 25% of your final exam score. Set that equal to the grade you want and solve for the exam score, and you have the number you need.
Two things drive the answer: how far your target is above your current grade, and how heavy the final is. A heavy final makes big jumps possible but also makes a bad day expensive; a light final barely moves your grade either way.
When the answer is over 100% or below 0%
If you need more than 100%, the target isn't reachable on the final alone. The calculator shows the best grade you can still get with a perfect score, so you can set a realistic goal or ask about extra credit or a curve.
If the number is zero or negative, the grade is already locked in: even a 0% on the final keeps you at or above your target. Don't skip it, though. Many classes require you to take, or pass, the final to pass the course, and a zero would still drag your grade down to the minimum shown.
Making sure your inputs are right
Use the current grade from your gradebook only if it already reflects every category except the final. If a project or late homework is still ungraded, your current grade isn't final yet; work out the rest with the grade calculator first.
Letter grade cutoffs vary. Many schools use 90/80/70/60 for A/B/C/D, and plus/minus systems commonly put A- at 90, B+ at 87 and so on. Some teachers round 89.5 up to 90, and some don't round at all. The table shows the score needed for each cutoff so you can read off your own.
The final grade formula
Score needed = (target − current × (1 − w)) ÷ wClass grade = current × (1 − w) + final score × w- target = the class grade you want, as a percentage
- current = your grade before the final, as a percentage
- w = the final exam's weight as a decimal (25% = 0.25)
Example
- Your current grade is 84%, the final is worth 25% and you want an 85% in the class.
- The work so far counts for 75%: 84 × 0.75 = 63 points banked.
- Score needed = (85 − 63) ÷ 0.25 = 22 ÷ 0.25 = 88%.
- For a 90%, you'd need (90 − 63) ÷ 0.25 = 108%, which isn't possible: a perfect final gives 63 + 25 = 88%.
- For an 80% you need (80 − 63) ÷ 0.25 = 68%, and a 60% is guaranteed: even a 0 on the final leaves you at 63%.
Frequently asked questions
What do I need on my final to keep an A?
Plug in your current grade, the final's weight and 90% (or your school's A cutoff). With a 94% and a 20% final, you need (90 − 94 × 0.8) ÷ 0.2 = 74% to stay at 90%.
How much will my final exam affect my grade?
At most, by its weight times the gap between your current grade and your exam score. With an 84% and a 25% final, a perfect score raises you to 88% and a zero drops you to 63%.
What if the final is worth points instead of a percentage?
Divide the final's points by the total points in the class to get its weight. A 200-point final in a 1,000-point class is worth 20%.
Can I fail the class if I fail the final?
Mathematically, only if your grade with a 0 falls below passing. But some classes require passing the final regardless of your average, so check the syllabus.
Why does it say I need more than 100%?
Your target is higher than what your current grade allows. The highest grade still possible is your current grade × (1 − final weight) + the final weight, which the calculator shows.
Sources
Last reviewed for 2026. How we calculate.