- Your grade right now, as a percentage, before the final is counted.
- How much the final is worth, as a percentage of the whole course grade.
- The overall grade you want when the course ends.
It returns the score you need on the final. If that score is above 100, it says the target is out of reach and shows the best grade you can still finish with. If you already have the grade locked in, it says so, and shows the lowest course grade you could end up with.
The formula
Your course grade is a blend of two parts. The part that is already graded makes up everything except the final, and the final makes up the rest. With the final weight written as a fraction (30% is 0.30):
course grade = current grade x (1 minus final weight) + final score x final weight
Rearranged to solve for the final:
needed score = (target grade minus current grade x (1 minus final weight)) divided by final weight
The "current grade" has to be your grade on everything except the final. If your online gradebook already counts the final as a zero, the number it shows is not the one to enter. Use the grade from the categories that have actually been scored.
A worked example
Your current grade is 82, the final is worth 30%, and you want an 85.
Everything else is worth 70% of the course, so it contributes 82 x 0.70 = 57.4 points. You need 85 in total, so the final has to supply 85 minus 57.4 = 27.6 points. The final is worth 30%, so you divide: 27.6 / 0.30 = 92. You need a 92 on the final.
Three other cases show how the answer can change shape:
- A 70 current grade, a 10% final and a target of 90 needs 270. That is impossible. The best possible result is 63 + 10 = 73.
- A 95 current grade, a 25% final and a target of 80 needs only 35.
- A 98 current grade, a 15% final and a target of 70 needs nothing. Even a zero leaves you at 83.3.
The weight does most of the work. A final worth 10% hardly moves a grade, and one worth 40% can change a letter. If the weight is a guess, check your syllabus before you panic or relax.
Why finals are worth different amounts
There is no standard weight for a final. Two school policies show how far apart the structures can be.
In Broward County, Florida high schools, each semester grade is made of two quarter grades at 37.5% each and an exam at 25%. For a few year-long courses with a state end-of-course exam, that exam counts as 30% of the final course grade.
At Cab Calloway School of the Arts in Delaware, the final course grade is the average of four quarter grades, each with a weight of 2, and the mid-year and final exams, each with a weight of 1. That makes each exam a tenth of the grade and each quarter a fifth.
College courses are set by the instructor, so the syllabus is the only place to find the number.
To try the Broward structure, say your two quarters were 84 and 91 and you want a 90 for the semester. Together the quarters give 87.5 over 75% of the grade, and you need 97.5 on the exam.
Where the target comes from
Your target should be a percentage cutoff from your own grading scale. Typical cutoffs vary. Green Bay's public schools list 93 as the bottom of an A, with 90 as an A-. The College Board's example chart draws the A line at 90. A percentage that is an A at one school is an A- at another. Ask whether your teacher rounds, too, because 89.6 can mean different things in different classrooms.
If you also want to see what the letter means for your GPA, put it into the high school or college calculator after you have your target.
What happens to the course grade afterward
Your final course grade is turned into a letter and points, and that letter is what goes on the transcript. Colleges that recalculate GPA work from those course grades, not from your percentages. The University of Georgia, for example, says it converts each grade according to the grading scale in use at your high school and then applies its own rules. So the score you need on a final matters mostly through the letter it produces, and a point or two on the wrong side of a cutoff is where the real difference sits.
Common mistakes
- Using the final's weight as a number of points. A 100-point final in a 1,000-point course is 10%, not 100%.
- Entering the grade that already includes the final.
- Forgetting extra credit or dropped scores, which can raise the true current grade.
- Chasing an unreachable target. If the answer is above 100, the useful question is what grade is realistic, and the calculator's best-possible figure answers that.
- Assuming a required score is a promise. Teachers curve some exams and round some grades, and the calculator cannot see either. Its result is the arithmetic of the weights you entered.
The cutoffs the calculator can use
The calculator does not round your target or the score you need until it shows two decimals. The quick-pick buttons use the A, B, C and D cutoffs from the scale chosen in the settings. Published cutoffs differ:
| Scale | A from | B from | C from | D from |
|---|---|---|---|---|
| Plus/minus with A at 93 (tool default; Green Bay) | 93 | 83 | 73 | 63 |
| 10-point, whole letters (NC state scale, Broward core) | 90 | 80 | 70 | 60 |
| Plus/minus with A+ at 97 (Forest Hills, OH) | 93 | 83 | 73 | 65 |
| Plus/minus, no D- (Alexandria City HS, VA) | 93 | 83 | 73 | 60 |
| Broward County: B+ and C+ bands but no extra points | 90 | 80 | 70 | 60 |
| College Board example chart (letters only) | 90 | 80 | 70 | 66 |
| Old 7-point scale (NC before 2015-16) | 93 | 85 | 77 | 70 |