Because final class grades are usually given either as letters (A, B+, etc.) or as percentiles (87, 92, and so on), you might be a little stuck on how to convert them into the decimals used to calculate GPA. No worries  this article is here to help! Keep reading to see how to translate all your grades into GPAready numbers.
What Is a GPA?
GPA stands for "grade point average" and it is exactly that: an average of all the final class grades that you received during your high school career. The GPA scale converts the letter and percentile grades your school gives you into a decimal typically ranging from 0.0 to 4.0, and then uses those decimals to calculate one summary number.
Your GPA is one of the most important pieces of your college application. It allows colleges to very quickly assess your intelligence, skills, work ethic, and willingness to challenge yourself. At the same time, it’s a way for them to see how you stack up against other people who graduated from your school, and all of the other applicants. Think about it: for an admissions officer, it's easy to have one handy number that compares you with other applicants at a glance. It's way harder to have to round up each of your grades, then compare them with each of the other person's grades, and so on and so forth for thousands and thousands of applicants.
Sisyphus thinks about going through applicants one grade at a time and is all, "Uh, no thanks, I'll stick with the giant boulder."
How Are Letters and Percentiles Converted Into GPA Scale?
Different schools use different systems to convert your grades into your GPA. Sometimes, they take the difficulty level of your classes into account, and sometimes all classes are treated the same.
Sure, they're both pumpkins  but a weighted comparison would be helpful.
Unweighted GPA Conversion
Most schools use an unweighted GPA. This means that all of your final grades get equal treatment, so grades earned in honors/AP courses get the same numerical value as grades earned in standard/college prep courses.
In other words, if Matan gets an A in AP Calculus and Camille gets an A in standard level Chemistry, they will both convert these A’s to 4.0.
Here is the typical conversion scale for an unweighted GPA:
Letter Grade 
Percentile 
GPA 
A+ 
97100 
4.0 
A 
9396 
4.0 
A 
9092 
3.7 
B+ 
8789 
3.3 
B 
8386 
3.0 
B 
8082 
2.7 
C+ 
7779 
2.3 
C 
7376 
2.0 
C 
7072 
1.7 
D+ 
6769 
1.3 
D 
6566 
1.0 
F 
Below 65 
0.0 
Weighted GPA Conversion
Some schools also calculate a weighted GPA. This grade point average takes into account how challenging each course actually is. So, final class grades in Honorslevel courses have .5 added to them, while final grades in AP/IB courses have 1 added to them. For this reason, weighted GPA scales usually range from 0.0 to 5.0.In our previous example, since Matan's A came from an AP class, it would convert to 5.0. Meanwhile Camille’s A, which came from a standard class, would become 4.0.
The typical weighted GPA conversion scale looks like this:
Letter Grade 
Percentile 
Honors GPA 
AP/IB GPA 
A+ 
97100 
4.5 
5.0 
A 
9396 
4.5 
5.0 
A 
9092 
4.2 
4.7 
B+ 
8789 
3.8 
4.3 
B 
8386 
3.5 
4.0 
B 
8082 
3.2 
3.7 
C+ 
7779 
2.8 
3.3 
C 
7376 
2.5 
3.0 
C 
7072 
2.2 
2.7 
D+ 
6769 
1.8 
2.3 
D 
6566 
1.5 
2.0 
F 
Below 65 
0.0 
0.0 
StepbyStep Conversion Examples
Let's work through a couple of examples to see how grade conversion works for a transcript that uses letter grades and one that uses percentile grades.
How to Convert Letter Grades Into a GPA
First, let's check out a transcript where final grades are given as letters by taking a look at the high school career of renowned secret operative John Doe:
Here's how its conversion works. Using the unweighted conversion table from before, we can see that, yearbyyear, the grades John earned are:
9^{th} Grade 
10^{th} Grade 
11^{th} Grade 
12^{th} Grade 
2.7 
2.3 
3.0 
4.0 
2.7 
4.0 
3.3 
3.0 
2.3 
3.0 
2.0 
3.0 
4.0 
2.7 
2.7 
3.3 
3.7 
3.0 
3.3 
4.0 
3.3 
3.3 
3.7 
2.3 
2.0 
4.0 
2.0 
2.0 
4.0 
3.0 
4.0 



3.0 

Now, to figure out John's GPA, first we have to add up his grades to get the sum. Then we have to count how many classes he took. Finally, we divide the sum by the number of classes and round to the nearest tenth:

9^{th} Grade 
10^{th} Grade 
11^{th} Grade 
12^{th} Grade 
Total 
Grade Sum 
28.0 
25.3 
27.0 
21.6 
101.9 
Number of Classes 
8 
8 
9 
7 
32 
So:
101.9 / 32 = 3.1 (John's cumulative high school GPA)
To figure out the GPA John would submit on college applications, we just leave off the senior year grades and repeat the same process:
28 + 25.3 + 27 = 80.3 (sum of final grades from 9th to 11th grade)
8 + 8 + 9 = 25 (number of classes taken from 9th to 11th grade)
80.3 / 25 = 3.2 (GPA sent on college applications)
How to Convert Percentiles Into a GPA
The process for converting percentiles into GPA is almost exactly the same. Let’s see it in detail by calculating the GPA of John’s archrival and spy nemesis, Jane Smith:
First, we'll convert her grades into GPA scale, and then find the sum and the number of courses she took:

9^{th} Grade 
10^{th} Grade 
11^{th} Grade 
12^{th} Grade 
Total 

4.0 
3.3 
3.7 
4.0 


3.7 
2.7 
4.0 
3.7 


3.3 
2.3 
3.0 
4.0 


2.3 
4.0 
4.0 
3.3 


4.0 
3.0 
2.7 
3.7 


3.3 
3.7 
3.3 
2.3 


3.0 
3.3 
3.7 
3.0 


3.7 
3.3 
4.0 
3.3 

Sum 
27.3 
25.6 
28.4 
27.3 
108.6 
Number of Courses Taken 
8 
8 
8 
8 
32 
So:
108.6 / 32 = 3.4 (Jane's cumulative high school GPA)
And, leaving off the senior year we see that:
81.3 /24 = 3.4 (the GPA she will submit to colleges)
What’s Next?
Still confused about how weighted and unweighted GPA calculations work? Let us help you figure it all out with our comprehensive explanation.
Worried about how your GPA will measure up? We explain what a good or bad GPA score is, and run the numbers on the average high school student.
Want to improve your SAT score by 160 points or your ACT score by 4 points? We've written a guide for each test about the top 5 strategies you must be using to have a shot at improving your score. Download it for free now:
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Anna scored in the 99th percentile on her SATs in high school, and went on to major in English at Princeton and to get her doctorate in English Literature at Columbia. She is passionate about improving student access to higher education.