How to Calculate GPA
The full formula behind every GPA, explained step by step with worked examples — or skip the arithmetic entirely with the GPA calculator.
The Four Steps
- Convert each letter grade to grade points. A/A+ = 4.0, A- = 3.67, B+ = 3.33, B = 3.0, and so on down to F = 0.0 — the full table is below.
- Multiply grade points by credit hours for every course. This is that course's quality points.
- Add up the quality points across all your courses.
- Divide the total by your total credit hours. That result is your GPA.
Three courses in one term:
- Chemistry (4 credits, grade A) → 4 × 4.0 = 16.0 quality points
- History (3 credits, grade B) → 3 × 3.0 = 9.0 quality points
- Statistics (3 credits, grade B+) → 3 × 3.33 = 9.99 quality points
Total: 10 credit hours, 34.99 quality points. GPA = 34.99 ÷ 10 = 3.50.
The Grade Point Scale
| Letter grade | Grade points |
|---|---|
| A+ / A | 4.00 |
| A- | 3.67 |
| B+ | 3.33 |
| B | 3.00 |
| B- | 2.67 |
| C+ | 2.33 |
| C | 2.00 |
| C- | 1.67 |
| D+ | 1.33 |
| D | 1.00 |
| F | 0.00 |
This is the standard US scale used by this site's calculators. Some schools use whole letters only (no plus/minus); a few use a 4.33 scale where A+ outranks A. Check your registrar if your numbers don't quite match.
Why Credit Hours Change Everything
The single most common GPA mistake is averaging letter grades directly instead of weighting them by credit hours. An A and a B don't average to a B+ if the A was a 1-credit seminar and the B was a 4-credit lab science — the heavier course should pull the average further toward itself.
Same two grades, weighted correctly:
- Seminar (1 credit, A = 4.0): 1 × 4.0 = 4.0 quality points
- Lab science (4 credits, B = 3.0): 4 × 3.0 = 12.0 quality points
Total: 5 credits, 16.0 quality points. GPA = 16.0 ÷ 5 = 3.20 — much closer to the B than a naive average of "A and B is a B+" would suggest.
Adding a New Term to a Running GPA
Your school doesn't store a running total of quality points anywhere visible — only your GPA and your total credits. To fold a new term into an existing GPA, rebuild the missing quality points by multiplying your old GPA by your old credit hours, add the new term's quality points, and divide by the combined credit hours. See what cumulative GPA means for the full walkthrough, or just use the GPA calculator, which does this automatically.
Common Mistakes
- Averaging grades instead of quality points — always multiply by credit hours first.
- Counting a repeated course twice when your school's policy is to replace the old grade — check your repeat policy before entering a retake.
- Including Pass/Fail courses as a specific grade — most schools exclude them from GPA entirely.
- Mixing a weighted number into an unweighted calculation — see weighted vs unweighted GPA for why this matters.
Frequently Asked Questions
What is a quality point?
A quality point is a course's grade points multiplied by its credit hours. It's the unit GPA is actually built from — a 4-credit A is worth twice the quality points of a 2-credit A, even though both are the same letter grade.
Can I calculate GPA without knowing credit hours?
Only as a rough estimate, by averaging grade points with no weighting — this treats every course as equal, which is rarely how a real transcript works. Credit hours are required for an accurate GPA.
Does GPA calculation differ between high school and college?
The formula is identical. What differs is the size of typical credit hours (college courses are usually 3-4 credits versus 1.0 for a year-long high school class) and whether a weighted scale for AP/Honors classes is in use, which is more common in high school.