What quarter credits do to your CASPA GPA
If your undergrad ran on the quarter system, your transcript shows credits in a unit CASPA does not use. The conversion math is simple - quarter credits times two-thirds - but the consequences for your GPA are not, and the applicants who hit them hardest are the ones who didn't know the conversion was happening at all.
The conversion in one sentence
Every quarter credit hour on your transcript becomes 0.667 semester credit hours on your CASPA-verified application. Three quarter credits become two semester credits. A 4-credit quarter course becomes 2.67 semester credits. The grade itself doesn't change, but the credit weight underneath it does, and that's the part that ripples through every GPA CASPA computes.
Who this applies to
If you went to one of the quarter-system schools - most of the University of California system, Stanford, Northwestern, Dartmouth, the Cal State system that's still on quarters, the University of Washington, the University of Chicago in some programs - your transcript is in quarter credits. CASPA sees that, applies the conversion, and reports your GPA in semester-credit terms.
If you transferred between a quarter-system school and a semester-system school, your transcript will show both, and CASPA converts only the quarter portion. The semester portion stays as-is. The result is a single CASPA cumulative GPA that blends the two using the same weighted-average math your transcript uses, but with the quarter credits scaled down to semester equivalents first.
What this does to your GPA
The grade doesn't change. The credit weight does. Whether your GPA goes up, goes down, or stays roughly the same depends on how the credit is distributed across grades.
If you got an A in a 5-credit quarter course, that course used to weigh 5 quality points × A toward your GPA. After conversion, it weighs 5 × 0.667 = 3.33 quality points × A. The contribution shrinks. If you got a C in a 5-credit quarter course, the same shrinking happens - your C contributes less to the GPA after conversion.
Where this matters most is when your quarter-credit distribution is uneven across grades. If your A's were in 5-credit lab courses and your B's were in 3-credit lectures, the conversion shrinks the A's faster than the B's, and your CASPA-verified GPA can drop by 0.05 to 0.15 versus what your transcript shows. That's not a transcript error, it's just the math.
The 0.05–0.15 swing in real terms
A 3.65 transcript GPA can land at 3.50 on CASPA. A 3.55 can land at 3.40. The actual delta depends on your specific credit-grade distribution, but in the IUPUI + Kaplan ground-truth case the Transcript Mapper calibrated against (one applicant with semester + quarter credits, three withdrawals, one retake), the predicted Combined Science GPA was 3.564 and the actual CASPA-verified Science GPA was 3.56. The difference between transcript-reported and CASPA-reported was about 0.08 - well inside the band of "this matters for the school list."
The math, with an example
Say you took five quarter courses last term:
- BIOL 1A - General Biology - 5 quarter credits - A
- CHEM 2A - General Chemistry - 5 quarter credits - B
- MATH 16A - Calculus - 4 quarter credits - A
- ENGL 3 - Composition - 4 quarter credits - B
- PHIL 7 - Logic - 3 quarter credits - A-
That's 21 quarter credits. After conversion, that's 21 × 0.667 = 14.0 semester credits. Your weighted GPA on the original quarter credits and on the converted semester credits comes out to the same number - about 3.65 - because the credit-hour weights scale uniformly. The shift you'd see is at the cumulative level, when this term's credits get blended with other terms or with semester-system transfer credits at different grades.
Where the surprise hits
The pattern most applicants miss is what happens to the science GPA CASPA recalculates. Quarter-system schools tend to schedule lab-heavy science courses at higher credit loads (5-credit Bio with lab, 5-credit Chem with lab) than semester-system schools (4-credit Bio with lab, 4-credit Chem with lab). When CASPA shrinks those high-credit science courses by a third, the science GPA moves more than the cumulative does - because science credits make up a larger share of your CASPA-counted load.
An applicant whose transcript shows a 3.7 cumulative and 3.6 science GPA can end up with a 3.6 cumulative and 3.45 science GPA on CASPA. The cumulative drops 0.10. The science drops 0.15. School-list strategy built around matriculant medians that assumed the transcript GPA is now built around a different number, and most applicants find this out after they submit - not before.
How to know before you submit
The Transcript Mapper applies the 0.667 conversion automatically on every quarter-credit row, then runs the same retake averaging, withdrawal counting, and BCPM reclassification CASPA does. The output is a row-by-row table of every course on your transcripts with the converted credits, the reclassified Subject Category, and the predicted Cumulative, Science, Non-Science, Last 60, Post-Bacc, and Graduate GPAs at the bottom. The mapper now lives inside the Application Dashboard - the engine works, accuracy is being refined as more transcripts go through. Your submission becomes part of the calibration set.
If you went to multiple schools
The mapper handles up to four transcripts in a single submission. Combined-school applicants - quarter undergrad to semester post-bacc, or two undergrads on different systems, or undergrad plus a separate prereq-completion school - get a single combined CASPA-style summary that mixes the units correctly. This is the case the mapper was originally built around because the math is the most error-prone there.
What I didn't realize when I was applying
(For applicants who learned this gap during their first cycle, the reapplicant playbook covers how to rebuild the school list around the corrected number.) I came out of an undergrad on the semester system, so the conversion didn't apply to me directly, but applicants I've talked to from UC and Stanford have all said the same thing - they didn't know the conversion was happening, and the gap between transcript GPA and CASPA GPA was the deciding number on whether their school list was the right list. If you're on the quarter system, do the conversion math before you build your list. The numbers are different than you think.
Frequently asked
Does CASPA convert grade points or just credits?
Just credits. The grade letter and grade points stay the same. Only the credit-hour weight shrinks, and the weighted average is recomputed using the new weights.
What about quarter-credit lab fees and pass/fail courses?
Pass/fail courses don't move GPA either way (no quality points). Course fees aren't part of CASPA's calculation. The conversion only applies to graded credits.
Does this affect my prereq fulfillment?
Yes, sometimes. PA programs typically state prereq requirements in semester credits ("4 semester credits of General Chemistry"). If your quarter-credit course was a 5-credit Chem, that's 3.33 semester credits after conversion - short of a 4-credit requirement. Most programs accept the conversion, but a few specify that prereqs must be at least the named semester-credit count, which means a single 5-credit quarter Chem doesn't fulfill a 4-credit semester requirement. The Program Spreadsheet has the per-program prereq credit requirements; cross-reference those against your converted credits.
How does the mapper handle a transcript that's mixed semester and quarter?
It detects the unit per row (most transcripts mark the unit explicitly in a header or footnote) and applies conversion only to the quarter rows. The output shows both original and converted credits side by side so you can see the math.