The GPA Formula
Every GPA calculation, no matter how many classes or semesters involved, comes down to one formula:
Grade points are calculated per class by multiplying the point value of your letter grade by that class's credit hours. Add those up across all your classes, then divide by your total credits - not the number of classes.
Step 1: Convert Each Grade to Points
Using the standard 4.0 GPA scale, an A is worth 4.0 points, a B is worth 3.0, a C is worth 2.0, and so on down to an F at 0.0. Plus and minus grades sit between these whole numbers - a B+ is 3.3, for example.
Step 2: Multiply by Credit Hours
Not every class counts equally. A 4-credit lab science class affects your GPA twice as much as a 2-credit elective. Multiply each grade's point value by its credit hours to get that class's total grade points:
| Class | Grade | Points | Credits | Grade Points |
|---|---|---|---|---|
| Biology | A | 4.0 | 4 | 16.0 |
| English | B+ | 3.3 | 3 | 9.9 |
| History | B | 3.0 | 3 | 9.0 |
| PE | A | 4.0 | 1 | 4.0 |
| Total | 11 | 38.9 |
Step 3: Divide to Get Your GPA
That's a 3.5 GPA for the semester - a strong, above-average result.
Calculating Cumulative GPA
Your cumulative GPA works the same way, just across every semester at once. Add together the grade points from every semester, and divide by your total credits across your entire academic career (not the number of semesters). See our dedicated guide on calculating cumulative GPA for a full multi-semester example, or use the cumulative GPA calculator to do it instantly.
Weighted vs Unweighted GPA
Everything above describes an unweighted GPA, capped at 4.0. If you're taking AP, IB, or Honors classes, your school may use a weighted scale instead, where an A in an AP class is worth 5.0 instead of 4.0. Read our full weighted vs unweighted GPA guide to understand which one your school reports.