What is GPA?
Your GPA (Grade Point Average) is a number that represents all of the letter grades you earned in either high school or college. Condensing the grades on your transcript into one number gives colleges and businesses a quick overview of your academic success and helps you keep track of your educational goals.
Thankfully, our GPA calculator does the number crunching for you, but the calculations aren't magic. Keep reading to find out how a GPA is calculated and learn the difference between high school (weighted or unweighted) and college GPAs.
GPA Scales
GPA calculation starts by converting your letter grade into a number. In the typical 4.0 scale, each is assigned a number from 04:

A = 4.0

B = 3.0

C = 2.0

D = 1.0

F = 0.0
Other than wondering why American schools skip the letter "E", it seems pretty easy, right? Not quite.
The GPA scale isn't standardized and varies from school to school. For example, some schools use a 05 or 04.5 weighted scale to award more points for AP or honors classes. We'll show you how to calculate a weighted GPA later on, but the bottom line is to make sure you look up the particular scale your school uses to convert letter grades into number points.
Many schools also use "+" and "" in addition to simple letter grades, and this is often reflected in the grade points by adding or subtracting 0.3 points. That way, a B+ will convert to 3.3 grade points, a B will still be 3.0 points, and a B converts to 2.7 grade points. The exception is that an A and an A+ are usually both worth 4.0 points.
What happens if your grade was given as a percentage instead of a letter grade? No worries, just use our percentage conversion chart to find the common conversions between percentages and letter grades.
Calculating High School GPA: Weighted vs. Unweighted
Some schools use a weighted GPA scale to account for more difficult classes. After all, an "A" in AP Calculus probably took a lot more work than an "A" in a regular class. A common weighted system adds 1 point for an AP or IB class, and 0.5 points for an honors class. In this way, an "A" in an AP class converts to 5.0 grade points, and a "B" is an AP class is worth 4.0.
We'll start by calculating an unweighted high school GPA using the basic 04 scale, and then spice it up a bit with a weighted GPA calculation.
Unweighted High School GPA
A basic GPA is calculated by converting every letter grade to a grade point number and then finding the average. So after the letter grades are converted to numbers, simply add up all of the grade points and then divide by the number of classes.
Total Grade Points ÷ Total Number of Classes = GPA
Here is Julie's report card for this semester. She took 5 classes, earning 4 "A"s and 1 "B".
Course  Letter Grade  Grade Points 

English  A  4.0 
Algebra II  A  4.0 
PhysEd  A  4.0 
Biology  A  4.0 
World History  B  3.0 
We start by converting the letter grades into grade points. Since we're using an unweighted 04 scale, her "A" in English converts to 4.0, while her "B" in World History is only worth 3.0.
To find her GPA, all we have to do is total all of her grade points (19) and divide by the number of classes she took (5).
19 ÷ 5 = 3.8 GPA
Weighted High School GPA
Weighted GPA is calculated in much the same way as unweighted, except not every class is on a 4.0 scale. Remember, AP and IB classes are usually on a 5.0 scale and honors classes typically use a 4.5 scale, so be careful to assign the correct grade points. The rest of the calculation follows the basic GPA formula.
Here's a look at a rather ambitious semester with 2 AP classes, 1 honors class, and 2 regular classes:
Course  Letter Grade  Grade Points 

AP English  B  4.0 (An AP class, so a “B” is “4.0”) 
AP Algebra  A  5.0 (An AP class, so an “A” is “5.0”) 
PhysEd  A  4.0 (A regular class, so an “A” is “4.0”) 
Chemistry I  B  3.0 (A regular class, so a “B” is “3.0”) 
Honors World History  A  4.5 (An honors class, so an “A” is “4.5”) 
Once the points are assigned according to the weighted scale, finding the GPA is as simple as adding up all of the points (20.5) and dividing by the number of classes (5).
20.5 ÷ 5 = 4.1 Weighted GPA
Even with 2 "B"s, the weighted GPA reflects the fact that this student took harder classes. You'll notice a weighted GPA allows for a number higher than 4.0. When reviewing applications, colleges take into account the differences between weighted and unweighted GPAs. If your school uses a weighted system, it's nice to get credit for taking harder classes, but remember that a truly impressive weighted GPA will be closer to 5.0.
Calculating College GPA
In calculating college GPA, course credit hours are thrown into the mix. Most college courses are 3 credit hours, but some are worth more depending on the difficulty of the class or extra work like science and computer labs.
Just like high school, the letter grade is first converted to grade points (usually according to the 4.0 scale). After that, the grade points are multiplied by the number of credit hours that the class is worth.
Say you took an English 101 course worth 3 credit hours and made an "A". To find the total number of points, multiply the credit hours (3) by the grade points (4.0).
3 credit hours x 4.0 grade points = 12 total points
The entire semester might look something like this:
Course  Letter Grade  Grade Points  Credit Hours  Total Points 

English 101  A  4.0  3  12 
Algebra 101  B  3.0  3  9 
Biology 101  B  3.0  4  12 
Computer Science  B  3.0  4  12 
Psychology 101  A  4.0  3  12 
Total  –  –  17  57 
You'll notice that the credit hours weight the more difficult classes to make them worth more points. Courses that include the extra work of a lab are often worth more credit hours, so a "B" in Biology 101 is worth the same number of total points as an "A" in English 101.
To find the semester GPA, add all of the total points (57) and divide by the number of credit hours (17).
57 ÷ 17 = 3.35 GPA
Cumulative vs. Semester GPA
A cumulative GPA takes all of the grade points earned across all semesters and finds the overall grade point average.
Here's an example of 4 college semesters, with corresponding semester GPA, credit hours and total points:
Semester  GPA  Credit Hours  Total Points 

Semester 1 (Fall)  3.6  12  43.2 
Semester 2 (Spring)  3.5  13  45.5 
Semester 3 (Fall)  3.8  12  45.6 
Semester 4 (Spring)  3.7  16  59.2 
Total  –  53  193.5 
We want the average GPA across all 4 semesters, but do not make the mistake of simply adding the semester GPAs together and dividing by 4. That won't give you an accurate average, since the credit hours per semester are different.
Instead, add up the total points (193.5) and divide by the number of credit hours (53). The result is:
193.5 ÷ 53 = 3.65 Cumulative GPA
A cumulative high school GPA is calculated in a similar way, just total all of the grade points and then divide by the number of classes.
Even better, use our cumulative GPA calculator. It handles all the calculations and even saves your current GPA so you can update it next semester!
Wrapping Up
Your GPA doesn't define you—after all, it would be impossible to fit your background, personality, and skills into one number. However, it is a strong indication to colleges and companies of how seriously you took your studies and how consistent you were with maintaining your grades.
A high GPA is worth the effort and will open doors for continued education or job opportunities. Thankfully, the steps to maintaining or raising your GPA are straightforward. Check out our guide to raising your GPA for tips on how to succeed.