Converting every course's credits by the same factor does not change the GPA of that course set, provided the grades and inclusion rules stay the same and you keep full precision. It changes the unit in which you express the credits.
When combining quarter-system courses with semester-system courses, however, you must put both sets into a consistent unit before calculating their relative weights.
Use the receiving institution's factor
Kent State describes a two-thirds conversion from quarter to semester credits. UW–Madison publishes a multiplier of 0.67. Those values are close, but not identical. Keep the institution's stated factor and rounding instructions with your worksheet.
Under an exact two-thirds model:
| Quarter credits | Semester equivalent |
|---|---|
| 3 | 2 |
| 4 | 8/3, approximately 2.6667 |
| 5 | 10/3, approximately 3.3333 |
| 6 | 4 |
The reverse factor for that exact model is 1.5. These arithmetic relationships do not decide whether a particular course transfers or satisfies a degree requirement.
Why the GPA stays the same
A credit-weighted GPA divides quality points by included credits. If every credit value is multiplied by a constant, that same constant appears in both the numerator and denominator, so it cancels.
Consider this hypothetical transcript:
| Course | Quarter credits | Grade | Assumed points | Quality points |
|---|---|---|---|---|
| Intro Biology | 5 | A− | 3.7 | 18.5 |
| College Writing | 4 | B+ | 3.3 | 13.2 |
| Calculus I | 5 | B | 3.0 | 15.0 |
| Studio Art | 3 | A | 4.0 | 12.0 |
Total credits: 17. Quality points: 58.7. GPA: 58.7 ÷ 17 = 3.452941…, displayed as 3.45.
Using exact two-thirds conversion throughout:
(58.7 × 2/3) ÷ (17 × 2/3) = 3.452941…
The result remains 3.45. Avoid rounding each course to one decimal place before calculating; that can change the relative weights and defeat the exact cancellation.
Combining records is a different problem
Suppose a separate record contains 12 semester credits at 3.0. Under the exact conversion above, the quarter record contributes 34/3 semester credits and 117.4/3 quality points. Add the second record's 12 credits and 36 quality points before dividing:
((58.7 × 2/3) + 36) ÷ ((17 × 2/3) + 12) = 3.22
This is a mathematical combined average under stated assumptions. A receiving institution may exclude transfer grades from its institutional GPA or apply other rules. Do not label this estimate as your new official GPA without checking.
A worksheet you can review
Keep original credits, converted credits, grade values, and inclusion decisions in separate columns. Record the conversion factor once, then apply it consistently. Preserve the original transcript so another person can reproduce your work.
Use the GPA calculator after normalizing the course credits and selecting the correct scale. Read the transfer-student GPA guide for the distinction between a planning calculation and a reported institutional result. A separate workspace helps keep the original record and converted scenario from being mixed together.
