How to Calculate a Percentage and Letter Grade

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For classroom teachers, grading tests and papers is second nature. However, if you are a homeschooling parent, you may be unsure about the best way to figure percentage grades, letter grades, and grade point average. You may not even be fully convinced that assigning grades is necessary, choosing instead to work to mastery on each assignment.

How to Calculate Percentage and Letter Grades

If you decide to grade your students’ schoolwork, use these simple steps to determine the percentage and letter grade for any assignment or test.

To calculate a grade, you will need to figure out the percentage of questions that your student answered correctly. All you need to know to find the grade is the total number of questions on the assignment and how many answers are correct. After that, you will just need to plug a simple equation into a calculator and convert the percentage to a letter grade.

Here's how:

  1. Correct the paper.
  2. Determine the number of total questions.
  3. Count the number of questions answered correctly.
  4. Take the number of correct answers and divide by the total number of questions. (Example: 15 correct answers divided by 20 total questions equals 0.75)
  5. Multiply this number by 100 to turn it into a percentage. (Example: 0.75 multiplied by 100 equals 75%)
  6. Grade ranges often vary among professors and teachers. However, a typical, easy-to-use grade scale is:
    • 90-100% = A
    • 80-89% = B
    • 70-79% = C
    • 60-69% = D
    • 59% and below = F

Using the examples above, 75% would earn a C letter grade.

How to Calculate GPA

If you’re homeschooling high school, you will likely need to figure your student’s overall grade point average (GPA) for his high school transcript. Calculate the cumulative GPA by dividing the total number of grade points earned by the number of credit hours attempted.

A typical grade point scale is:

  • A = 4.0
  • B = 3.0
  • C = 2.0
  • D = 1.0

There are variances for +/- grades that will vary based on the percentage grade scale you use. For example, if you use the ten points per letter grade scale, a 95% might indicate an A- which would translate to a grade point of 3.5.

Here’s how:

To figure out your student’s cumulative GPA:

  1. Determine the total number of grade points earned. For example, if your student received three A’s and one B, his grade point total would be 15 (3x4 = 12; 1x3=3; 12+3=15).
  2. Divide the grade point total by the number of credits attempted. In the example above, if each course reflected one credit hour, your student’s GPA would be 3.75 (15 grade points divided by 4 credit hours = 3.75)

Why Do Homeschoolers Need Grades?

Many homeschooling families choose not to bother with grades since they don’t move on until a child fully understands the concept. Working to mastery means that the student would ultimately never earn less than an A.

Even if your homeschooling family works to mastery, there are a few reasons you may need to assign percentage or letter grades for your students.

Some students find the challenge of getting good grades motivational.

Some kids like the challenge of seeing how many answers they can get correct. These students are motivated by earning high scores. This may be especially true for kids who have been in a traditional school setting or those who homeschool using a more school-at-home approach. They don’t see the point of completing worksheets or tests if they don't receive a grade for their work.

Grades can provide valuable feedback for these students to understand how they are performing. 

Grades provide an objective means of assessing student performance.

Many homeschooling parents find it difficult to strike a balance between being overly critical and overly lax about their student’s academic performance. It can be helpful to create a grading rubric so that both you and your student know what’s expected.

A rubric can help you assess your student’s work objectively and force you to focus on specific issues. For example, if you’re working on teaching him to write a descriptive paragraph, a rubric can help you stay focused on descriptive elements and ignore run-on sentences or grammar errors until another assignment.

High school students may need grades for their transcript.

Even if you prefer not to assign grades in your homeschool, homeschoolers who will be applying for college admission may need them for their high school transcripts.

Some courses may be difficult to assign a percentage grade, particularly more interest-led topics. An alternative is to assign a letter grade based on your student’s understanding of the topic and the effort put forth in doing the work.

For example, a strong understanding and effort might earn an A. Solid knowledge and a decent but not outstanding effort might earn a B. You might assign a C if your student understands the topic well enough to move on without repeating the course and/or you would have liked to have seen more effort applied. Anything less would mean repeating the course. 

Some homeschooling laws may require grades.

Your state homeschooling laws may require submitting grades to the county or state school superintendent, umbrella school, or other governing bodies. 

Assigning percentage and letter grades doesn't have to be difficult. These simple steps can make it easy no matter which route you choose.

Updated by Kris Bales


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Your Citation
Hernandez, Beverly. "How to Calculate a Percentage and Letter Grade." ThoughtCo, Aug. 27, 2020, Hernandez, Beverly. (2020, August 27). How to Calculate a Percentage and Letter Grade. Retrieved from Hernandez, Beverly. "How to Calculate a Percentage and Letter Grade." ThoughtCo. (accessed March 21, 2023).

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