To calculate GPA, convert each course's letter grade into grade points (A = 4.0, B = 3.0, and so on), multiply each course's points by its credit hours to get quality points, add the quality points together, then divide by total credit hours. Weighted GPA adds bonus points for Honors and AP/IB courses before this final division.
The GPA formula
GPA is a credit-weighted average, not a simple average of letter grades. Every course contributes quality points equal to its GPA points multiplied by its credit hours, and the GPA is the sum of quality points divided by the sum of credit hours.
- Convert each course's letter grade to GPA points using the 4.0 scale.
- Multiply each course's GPA points by its credit hours to get quality points.
- Add the quality points from every course.
- Divide total quality points by total credit hours.
Worked example
A student takes four courses in one term. The GPA is the total quality points divided by total credit hours, not a plain average of the four grades.
| Course | Grade | Points | Credits | Quality points |
|---|---|---|---|---|
| English | A− | 3.7 | 3 | 11.10 |
| Chemistry | B+ | 3.3 | 4 | 13.20 |
| History | A | 4.0 | 3 | 12.00 |
| Algebra II | B | 3.0 | 3 | 9.00 |
Weighted vs. unweighted GPA
An unweighted GPA caps every course's contribution at 4.0. A weighted GPA adds bonus points for more difficult courses — a common convention is +0.5 for Honors and +1.0 for AP or IB — before the credit-hour division, which is why a weighted GPA can exceed 4.0.
In the example above, if Chemistry were an AP course, its weighted points would be 3.3 + 1.0 = 4.3, raising both that course's quality points and the overall GPA.
Common GPA calculation mistakes
The most frequent error is averaging grade points directly without accounting for credit hours, which overweights low-credit courses and underweights high-credit courses. Another common mistake is applying a weighted bonus to a failing grade — most schools do not award bonus points for an F regardless of course level.
Grade Calculator Editorial Team
We create plain-language grading tools and educational guides, check every worked example against the underlying formula, and note where school or instructor policies can change the result.