Step 1: Convert each letter grade to grade points
On the standard 4.0 scale, each letter grade is worth a set number of grade points: A = 4.0, A− = 3.7, B+ = 3.3, B = 3.0, B− = 2.7, C+ = 2.3, C = 2.0, and so on down to F = 0.0.
Some schools use slightly different values (for example, awarding 4.33 for an A+ or using whole-letter grades only), so it's worth checking your school's official scale.
Step 2: Multiply grade points by credit hours
Courses aren't weighted equally — a 4-credit course counts more than a 1-credit one. Multiply each course's grade points by its credit hours to get its "quality points."
For example, an A (4.0) in a 3-credit course is worth 4.0 × 3 = 12 quality points.
Step 3: Add up and divide
Add all your quality points together, then divide by your total credit hours. That's your GPA.
Worked example: an A (4.0) in a 3-credit class, a B+ (3.3) in a 4-credit class, and an A− (3.7) in a 3-credit class gives (12 + 13.2 + 11.1) ÷ 10 = 3.63 GPA.