Most U.S middle schools, high schools and colleges use a five letter grading scale ranging from A to F to rate student performance. There is no letter grade E. The highest letter is an A (excellent) while the lowest is an F (failure). The letter grades are refined with pluses and minuses (+/-) to denote performance either slightly above or below the whole letter grade. Final letter grades for a class are reported on a student's report card at the end of the semester. Tests and assignments over the course of the year are typically marked with letter grades as well.
Each grade has a percentage equivalent range. The percentage of correct answers a student gets on a test or assignment is mapped to the equivalent letter grade. See the table below for percentage details. For example, a B letter grade is awarded for getting between 83% and 86% correct. Sometimes letter grades are not quantitatively based on a percent but are subjectively given by a teacher or professor based on their rating of a student's work. For example, a student who writes an excellent essay may earn an A if the teacher feels it demonstrates mastery of a subject.
Let's look at an example to see how a letter grade would be assigned for a student in a class. You can use this example to see how to calculate your own letter grade. During a semester, a student has a number of assignments and tests. Each with a maximum number of points possible to earn. The total points available for the semester are 300.
| Assignment | Points Possible | Points Earned |
|---|---|---|
| Homework | 10 | 10 |
| Quiz | 20 | 18 |
| Homework | 10 | 7 |
| Lab Activity | 15 | 12 |
| Test | 40 | 36 |
| Homework | 10 | 7 |
| Quiz | 20 | 17 |
| Homework | 10 | 7 |
| Test | 40 | 26 |
| Essay | 35 | 30 |
| Homework | 10 | 9 |
| Test | 80 | 72 |
| Total | 300 | 251 |
In this scenario, the student has earned 251 out of a possible 300 assignment and test points. We convert that to a percentage as follows.
Divide points earned by total points possible
251 ÷ 300 = 0.836
Multiply the result by 100 to obtain percentage
0.836 × 100 = 83.6%
Consulting the letter grade scale table further down this page, we see that a 83.6% equals a B letter grade in this class for the semester.
At the end of a semester, the teacher gives a letter grade summarizing the entirety of a student's work. Each letter grade has a grade point equivalent ranging from 4.0 to 0.0. An A is worth 4.0 grade points, an A- is worth 3.7 grade points, etc. The grade points for each class are then used to calculate a grade point average (GPA) for all of a student's classes. See the table below to see how letter grades relate to grade points.
Any grade B or above is considered good performance in a class. A C is not a good grade, but one or two isn't the end of the world. D's and F's are definitely bad grades and should be avoided if you plan on going on to college or even graduate.
Reference table of the letter grade scale with grade points and percent equivalents. This grading is used my most U.S. high schools and colleges using an unweighted 4.0 scale. Use this table to convert a letter grade to a GPA or percentage.
| Grade | Points | Percent |
|---|---|---|
| A+ | 4.0 | 97-100 |
| A | 4.0 | 93-96 |
| A- | 3.7 | 90-92 |
| B+ | 3.3 | 87-89 |
| B | 3.0 | 83-86 |
| B- | 2.7 | 80-82 |
| C+ | 2.3 | 77-79 |
| C | 2.0 | 73-76 |
| C- | 1.7 | 70-72 |
| D+ | 1.3 | 67-69 |
| D | 1.0 | 63-66 |
| D- | 0.7 | 60-62 |
| F | 0.0 | 59 or lower |