GPA math isn’t complicated, but it’s easy to get wrong by hand — especially once you’re averaging across a full semester of different credit loads. Here’s exactly how the calculation works.
The formula
Your GPA is a credit-weighted average of your grade points, not a simple average of your grades:
GPA = total quality points ÷ total credit hoursWhere “quality points” for each course = the grade’s point value × that course’s credit hours.
The standard 4.0 scale
Most US schools use some version of this scale:
| Grade | Points |
|---|---|
| A | 4.0 |
| A- | 3.7 |
| B+ | 3.3 |
| B | 3.0 |
| B- | 2.7 |
| C+ | 2.3 |
| C | 2.0 |
| C- | 1.7 |
| D+ | 1.3 |
| D | 1.0 |
| F | 0.0 |
Check your own school’s scale before relying on this for anything official — some schools round differently or don’t use plus/minus grades at all.
Worked example
Say you took three courses in a semester:
- Biology: 4 credits, grade A (4.0)
- English: 3 credits, grade B+ (3.3)
- Art: 2 credits, grade B (3.0)
Step 1 — quality points per course:
- Biology: 4.0 × 4 = 16.0
- English: 3.3 × 3 = 9.9
- Art: 3.0 × 2 = 6.0
Step 2 — add them up: 16.0 + 9.9 + 6.0 = 31.9 total quality points
Step 3 — add up credit hours: 4 + 3 + 2 = 9 total credits
Step 4 — divide: 31.9 ÷ 9 = 3.54 GPA
Notice that the higher-credit course (Biology, 4 credits) pulls more weight than the lower-credit one (Art, 2 credits) — that’s the entire point of weighting by credit hours instead of just averaging the three grade points directly (which would incorrectly give 3.43).
Cumulative GPA across multiple semesters
The math is identical — just include every course from every semester you want counted, each with its own original credit hours and grade, and run the same total-quality-points-over-total-credits calculation across all of them at once.
Common mistakes
- Averaging grade points without weighting by credits. A 1-credit elective and a 4-credit core class don’t count equally.
- Using the wrong scale. Some schools give extra points for AP/honors courses (a 5.0-scale weighted GPA); this calculator uses the standard unweighted 4.0 scale.
- Forgetting pass/fail or withdrawn courses usually don’t count toward GPA at all — check your school’s policy before including them.
Try it yourself
Our GPA calculator runs exactly this formula — add your courses with their credit hours and grades and it updates instantly. If you’re trying to figure out what you need on an upcoming final to hit a target grade, the final grade calculator does that math for you.