Your Grade Point Average (GPA) is a single number that summarizes how you performed across all your courses in a given term, weighted by how many credit hours each course was worth. Here's exactly how it's calculated, with the arithmetic shown in full.
The GPA formula
GPA = Σ(Grade Points × Credit Hours) ÷ Σ(Credit Hours)
In plain terms: for every course, multiply the grade points you earned by the course's credit hours. Add those totals together across all your courses, then divide by the total number of credit hours you took.
Step 1: Convert each letter grade to grade points
Most US institutions use a 4.0 scale. The standard conversion is:
| Letter Grade | Grade Points |
|---|---|
| A+ / 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 |
Not every school uses exactly this scale — some cap A+ at 4.0 rather than allowing it to exceed a B average, and some don't use plus/minus grading at all. Always check your registrar's official conversion table for your institution.
Step 2: Multiply grade points by credit hours
For each course, multiply its grade points by its credit hours. This gives you that course's "quality points."
Step 3: Add everything up and divide
Sum all your quality points, then divide by your total credit hours.
Worked example 1: A typical semester
Say you took four courses:
| Course | Credits | Grade | Grade Points | Quality Points |
|---|---|---|---|---|
| Calculus I | 4 | A | 4.0 | 16.0 |
| Physics I | 3 | B+ | 3.3 | 9.9 |
| English Composition | 3 | A- | 3.7 | 11.1 |
| Intro to Psychology | 3 | B | 3.0 | 9.0 |
Total credit hours: 4 + 3 + 3 + 3 = 13
Total quality points: 16.0 + 9.9 + 11.1 + 9.0 = 46.0
GPA = 46.0 ÷ 13 = 3.54
Worked example 2: A semester with a repeated course
Suppose you also failed a 3-credit course earlier and retook it:
| Course | Credits | Grade | Grade Points | Quality Points |
|---|---|---|---|---|
| Chemistry I (retake) | 3 | B- | 2.7 | 8.1 |
| History | 3 | A | 4.0 | 12.0 |
| Statistics | 4 | C+ | 2.3 | 9.2 |
Total credit hours: 3 + 3 + 4 = 10
Total quality points: 8.1 + 12.0 + 9.2 = 29.3
GPA = 29.3 ÷ 10 = 2.93
Note that whether the original failed attempt still counts toward your GPA depends entirely on your school's retake/grade-replacement policy — some replace the old grade, some average both attempts, and some keep both on record permanently.
Common edge cases
- Withdrawals (W): Typically excluded from GPA — no grade points, no credit hours counted.
- Incompletes (I): Usually excluded until a final grade is submitted, then recalculated.
- Audited courses: Not included in GPA at all since no grade is assigned.
- Transfer credits: Often count toward your total credit hours but many schools don't factor the transfer institution's grades into your GPA.
- AP / IB / honors weighting: Some high schools add extra grade points (e.g. +0.5 or +1.0) for advanced courses — see our Weighted GPA Calculator if your school does this.
Try it yourself
Rather than doing this arithmetic by hand every semester, our GPA Calculator does exactly the calculation above automatically — enter your courses, credits, and grades, and it computes your GPA instantly, saved privately to your browser with no account required.
