How the final grade calculator works
Your course grade is a weighted average with exactly two parts: everything you have already done, and the final. If the final is worth 20% of your grade, then everything before it is worth 80%, and those points are already banked. This calculator takes the one unknown, your score on the exam, and solves for it.
It then does the part most calculators skip. Rather than handing back a single number for a single target, it prints the score you need for every letter grade on your scale, and then turns the arithmetic around and shows what each possible exam score would actually leave you with. Most people arrive here asking about one grade and leave having realised the useful question was a different one.
The formula
Weight is the final's share of your grade written as a decimal, so a final worth 20% is 0.20. The Current × (1 - Weight) part is the number worth understanding: it is the points you have already locked in, and no exam score can touch it.
Worked example
You have an 88% going into the final, you want a 90%, and the final is worth 20% of your grade.
Banked points: 88 × 0.80 = 70.40 of the 100 available.
Needed = (90 - 70.40) ÷ 0.20 = 19.60 ÷ 0.20 = 98%.
Now the part that actually helps. A perfect final gives you 90.40%, and a zero leaves you at 70.40%. Your grade is landing somewhere in that 20-point band no matter what happens on the day. A 63 on the final still holds a B, and a C- is already yours even if you never open the book. Knowing the floor is often worth more than knowing the ceiling.
Why we show you the whole ladder
The honest problem with a single-answer final grade calculator is that it answers a question people ask before they have all the information. You type in the A you were hoping for, get told you need a 98, and close the tab feeling worse than when you opened it. Nothing about that is useful, and nothing about it is even complete.
So this page prints every letter. In the worked example above, the 98 for an A- sits directly above an 83 for a B+, a 63 for a B, and a 48 for a B-. Those are all real options, and seeing them together turns a single discouraging number into a set of choices. A student who knows a 63 protects a B can study for that with a clear head, which tends to produce a better exam than chasing a 98 with a sinking feeling.
How much can a final really move your grade?
Less than most people fear, and the arithmetic is simple. The entire distance between a zero and a perfect paper is exactly the final's weight. A final worth 20% can move your course grade by at most 20 percentage points, and only if you go from one extreme to the other. Realistically, the difference between a 75 and a 90 on that same final is three percentage points of course grade.
This cuts both ways and both are worth knowing. It means a single exam is very unlikely to rescue a grade that is far from where you want it. It also means a single exam is very unlikely to destroy one. Finals week produces a lot of dread that the numbers do not support.
Which grading scale is yours?
Scales genuinely differ between schools, which is why this calculator asks rather than assuming. On the plus / minus scale used by most colleges an A starts at 93. On the straight 10-point scale used by most US high schools it starts at 90. On the traditional 7-point scale an A also starts at 93, but the passing line sits at 70 rather than 60. A 91% is an A- on the first, a plain A on the second, and a B on the third. If you are near a boundary, pick the right one.
What to do when the number comes back above 100
It means that grade is not reachable through the final by itself, which is arithmetic and not a judgement. It is also much better to learn now than in three weeks. Two things are worth doing. First, look down the table for the best grade that is still a real number and aim at that one, because it is genuinely achievable and the one above it is not. Second, go and ask, because syllabi hide more flexibility than students expect: a dropped lowest quiz, an extra credit assignment, a late policy you have not used, or a final that replaces a lower test score. Those conversations go a great deal better when you arrive with the numbers already worked out.
Points-based classes
If your class counts total points rather than percentages, convert once and everything else works. Your current grade is the points you have earned divided by the points possible so far, times 100. The final's weight is the exam's points divided by the total points in the course. A 200-point final in a 1,000-point class is a weight of 20.