Finals week comes down to one question: what do I need on my final? This final grade calculator answers it from three numbers you already know: your current grade, the weight of the final exam and the grade you want in the class. It also shows what your overall grade becomes for a range of final exam scores, so you can see how much room you have.
Quick answer: Required final score = (desired − current × (1 − weight)) ÷ weight. With an 85% in the class and a final worth 30%, you need 68.33% for a B (80%), but 101.67% for an A, which is not possible. With a 92% and a 20% final, you need 82% to keep an A.
How to use the final grade calculator
- Enter your current grade in the class as a percentage (your gradebook’s number before the final).
- Enter the final exam weight from your syllabus, for example 20%, 25% or 30%.
- Enter the grade you want, or tap A (90%), B (80%), C (70%) or D (60%).
- Press Calculate to see the score you need and the grade each final score would give you.
How is the final exam grade calculated?
Your course grade is a weighted average: everything before the final counts for (1 − weight) and the final counts for the weight.
| What you want | Formula | Example (85% now, final 30%) |
|---|---|---|
| Overall grade after the final | current × (1 − w) + final × w | 85 × 0.7 + 75 × 0.3 = 82% |
| Score needed on the final | (desired − current × (1 − w)) ÷ w | (80 − 59.5) ÷ 0.3 = 68.33% |
| Grade if you score 0% | current × (1 − w) | 85 × 0.7 = 59.5% |
| Grade if you score 100% | current × (1 − w) + 100 × w | 59.5 + 30 = 89.5% |
What do I need on my final? Worked examples
Example 1: holding on to a B
Current grade 85%, final worth 30%, goal 80% (B).
- Points already locked in: 85 × 0.70 = 59.5
- Points still needed: 80 − 59.5 = 20.5
- Required final: 20.5 ÷ 0.30 = 68.33%
Scoring 100% would give 89.5%, just short of an A, so the A is not possible here.
Example 2: pulling up to a B
Current grade 78%, final worth 25%, goal 80%: (80 − 78 × 0.75) ÷ 0.25 = (80 − 58.5) ÷ 0.25 = 86%. A 90% on the final would give an 81% overall.
Example 3: keeping an A
Current grade 92%, final worth 20%, goal 90%: (90 − 92 × 0.8) ÷ 0.2 = (90 − 73.6) ÷ 0.2 = 82%. Even a zero would leave 73.6%, a C.
Example 4: a heavy final
Current grade 88%, final worth 40%, goal 90%: (90 − 88 × 0.6) ÷ 0.4 = (90 − 52.8) ÷ 0.4 = 93%. The heavier the final, the more a single exam can move your grade in either direction.
The tables below the calculator give the required score for every current grade from 70% to 95% with a final worth 20%, 25% or 30%.
How to read your result
- Under 70% needed: you have a comfortable cushion; focus on not bombing the exam.
- 70–90% needed: realistic with solid review. Practice exams are the best use of your time.
- Over 90% needed: possible but tight; ask about extra credit or dropped assignments.
- Not possible: aim for the next letter grade and check what that does to your GPA with the GPA calculator.
Have points on a test instead of a percentage? Turn them into a percent with the percentage calculator (for example 43 out of 50 is 86%). Counting down to exam day? The age calculator also works out the days between any two dates.
Common mistakes
- Using raw points instead of the weighted grade. Enter the percentage your gradebook shows, not points earned.
- Forgetting other remaining work. If a project is still ungraded, add its weight to the final’s weight only if it is graded like the final; otherwise the answer is approximate.
- Typing the weight as a decimal. Enter 30 for 30%, not 0.3.
- Assuming 90% is an A everywhere. Check your syllabus; some classes use 93% or a curve.
- Ignoring rounding rules. Some instructors round 89.5% up to an A; others do not.
This calculator assumes your current grade and the final weight add up to the whole course grade. Your instructor’s gradebook and syllabus are the final word.
Frequently asked questions
How do I calculate what I need on my final?
Use required final = (desired grade − current grade × (1 − final weight)) ÷ final weight, with the weight as a decimal. With an 85% in the class, a final worth 30% and a goal of 80%: (80 − 85 × 0.7) ÷ 0.3 = (80 − 59.5) ÷ 0.3 = 68.33%.
I have an 80% and the final is worth 20%. What do I need to keep a B?
You need 80% on the final: (80 − 80 × 0.8) ÷ 0.2 = 16 ÷ 0.2 = 80. When the final counts 20%, keeping the same grade always requires matching your current grade on the exam. Getting an A (90%) would need 130%, which is not possible.
What is the lowest score I can get on the final and still keep an A?
Set the desired grade to 90% (or your school’s A cut-off). With a 93% in the class and a final worth 25%, you need (90 − 93 × 0.75) ÷ 0.25 = 81%. The tables on this page list the answer for current grades from 70% to 95%.
How much will my final exam affect my grade?
Your overall grade moves by the final’s weight times the gap between your exam score and your current grade. With a 30% final, scoring 20 points below your current grade drops you 6 points overall; scoring 10 points above raises you 3 points.
What if the calculator says the grade is not possible?
It means you would need more than 100% on the final. Even a perfect score would leave you just short; the result shows how high 100% would take you. Ask your instructor about extra credit or a curve, or set a realistic goal one letter grade lower.
What does ‘secured’ mean?
Your current grade is high enough that even a zero on the final keeps your target. With a 95% and a final worth 20%, a zero still leaves you at 76%, a C. Many classes require you to take or pass the final, so do not skip it.
Is my current grade already weighted?
Most online gradebooks (Canvas, Blackboard, PowerSchool) show a weighted grade for everything graded so far, which is what this calculator expects. If your gradebook shows raw points instead, convert them to a percentage first: points earned ÷ points possible × 100.
What percentage is an A, B or C?
On the most common U.S. scale an A starts at 90%, a B at 80%, a C at 70% and a D at 60%; below 60% is an F. Some schools use stricter cut-offs such as 93% for an A, so type your syllabus’s number into the desired grade field.
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