Points vs. Percentages: Calculating your grade
You may have noticed that each teacher has his or her own system for evaluating classes. With all of the variation, how are you supposed to figure your final grade? There are a few basic systems that most instructors use. When in doubt, ASK!
The two main systems are very similar. One system assigns points to each assignment or exam, and then assigns the grade distribution based on the number of points you have accrued. The other system records the percent correct that you receive on each assignment, exam, etc. At the end of the semester, your total percentage in the course is used to assign your letter grade.
Points
Some instructors will tally the total number of points earned in a semester, and then will assign letter grades accordingly.
For example:
Hour Exams 300 
A 660 points 
Final Exam 200 
AB 640 
Laboratory 200 
B 575 
Other 100 
BC 555 
800 
C 500 

CD 480 

D 400 
In this example, the instructor has listed his assessment items (hour exams, final exam, laboratory work, and "other") and how many points are available in each.
Maybe, you received the following points:
Hour exam 1 
80 
Hour exam 2 
78 
Hour exam 3 
96 
Final Exam 
124 
Lab work 
175 
Other 
80 

Total 
633 
You totaled 633 points in the semester. According to the grading scale, you would receive a "B" in the course. Congratulations!
Advantages
There is very little math involved, and it becomes extremely easy to calculate your grade at the end of the semester. All you need to do is count and add! Many people prefer this method because they don’t need to worry about calculating percents for each assignment or exam.
Disadvantages
As you can see, your total number of points determines your grade. If you are one point shy of the next grade level, it can be much more frustrating! It can also be more difficult to see where the importance is put in a course—which is worth more: an exam, quiz, or individual homework assignment?
Percents
This is the "classic" method of grading. You still get a specific number of points on each assignment; instead of merely looking at the sum of all of your points, you look at the percent of points you earned on all of your assignments.
For example:
Grading 
Curve 
Homework 
25% 
A 
90100 
C 
7074 
Quizzes 
25% 
AB 
8589 
CD 
6569 
Midterm Exam 
25% 
B 
8084 
D 
6064 
Final Exam 
25% 
BC 
7579 
F 
Below 60 
In this method, you take the average of all of your points in each grading category. In this case, there are four: homework, quizzes, midterm, and final. To begin, find the average of all of your homework assignments. From the chart above, you can see that this is worth 25% of your grade. The average of all of your quizzes is 25% of your grade. Your midterm and final exams are each worth 25% of your grade. When you compute your final grade, you can "translate" your percentage into a letter grade using the curve above.
Perhaps you earned the following points:
Homework (out of 10 points) 
Quizzes (out of 15 points) 
Midterm Exam: 100 points 
Homework 1 
8 
Quiz 1 
15 

88 
Homework 2 
7 
Quiz 2 
13 


Homework 3 
6 
Quiz 3 
12 
Final Exam: 200 points 
Homework 4 
9 
Quiz 4 
15 

184 
Homework 5 
10 
Quiz 5 
10 


Homework 6 
10 
Quiz 6 
14 


Homework 7 
8 
Quiz 7 
15 


Homework 8 
9 
Quiz 8 
13 


Homework 9 
8 
Quiz 9 
15 


Homework 10 
6 
Quiz 10 
14 


Total: 
81 

136 


Average: 
81/(10pts*10 homeworks) =0.81 or 81% 
136/(15 pts *10 quizzes) =136/150=0.907 or ~91% 

After determining where you stand on your current assignments, you can figure out an approximate final grade.
Calculate the total points you received on all of your homework assignments. Next, calculate the total possible points earned on your homework assignments. You need both of these numbers to calculate the percent correct you have earned.
You received 81 total points out of your homework assignments. You received an 81% for the homework portion of your grade (so, by the curve above, about a B average).
You can do the same for your quiz grade. Your quiz grade is 90.7% (an A average).
Your midterm exam grade is 88%. You received an 88%, or an AB on the midterm.
Your final exam grade is 92%. You received an A on the final.
Now, you are ready to determine your final grade, as follows. Take the amounts you earned in each individual section; multiply them by the percent each section is worth. See below example:
Grading 
Your grade * % section is worth = 
=20.25 
Homework 
81*.25 
=22.675 
Quizzes 
90.7*.25 
=22 
Midterm 
88*.25 
=23 
Final 
92*.25 


Total 

87.925 
Your total is 87.925. By looking at the chart above, you would get an AB in the course.
Advantages
With percents, you can see how you are doing throughout the semester. It is easier to get an idea of how you are doing when all assignments are in.
Disadvantages
It becomes much more difficult to argue "one more point" to raise your grade. Since percents are based on your averages for your class, they are more indicative of how you are doing as a whole. One assignment is less apt to make or break your grade. There is also more work involved in computation (as you can see!).
Curves
There are many, many different types of grading curves.
Bell Curve
The standard curve is commonly called a "bell" curve. In this case, there is a specific number of each letter grade allowed. For example, in a class of 20, the top grade in the class would get an A, and the lowest grade would be an F. The middle 8 or so grades would be a C, and the rest become AB, B, BC, CD, or D. This curve will rank you in terms of your classmates. It is a system that can cause a large amount of animosity, and does not lend itself well to collaboration between students!
Preset Curve
Some people call their specific grade distribution a "curve." For example, one instructor at Edgewood uses the following:
90  100% 
A 
88  89% 
AB 
80  87% 
B 
78  79% 
BC 
70  77% 
C 
68  69% 
CD 
60  67% 
D 
Below 60% 
F 
The "curve" is already set, at the beginning of class. If you receive anywhere from 90100% on your work, you would receive an A. In this type of curve, you are competing only against yourself.
Random Curve
Occasionally, you can find the following statements in a syllabus:
"Keep in mind that this scale may change based upon overall class performance, but it will only be adjusted downward"
"This curve may be adjusted but only at the end of the semester after the final exam is graded and the numerical averages are completed."
This type of curve is put into place for your benefit! It means that the instructor had a specific "preset" curve in place when the semester started. After looking at all grades at the end of the semester, he or she may decide to adjust the scale to allow more students to receive As, Bs, Cs, etc. This type of curve will not harm your grade in any way; instead, it may boost you from an AB to an A!