GPAX and the Thai High School Grading System in TCAS Admission
By Muntasir Minhaz • Published Aug 07, 2026 • Study in Southeast Asia
GPAX is your cumulative grade average across every subject and semester of grades 10 to 12 (Mathayom 4 to 6), calculated on Thailand's 0 to 4 grading scale. Every TCAS round uses GPAX somewhere, but each faculty sets its own weight for it alongside test scores.
🎓 GPAX covers all subjects, weighted by credit hours, not just your major subjects.
Grades run from 0 (fail) to 4 (excellent) per subject in the Thai basic education system.
Applicants still finishing M6 usually submit GPAX from 5 completed semesters.
Graduated applicants submit GPAX from all 6 semesters of M4 to M6.
Portfolio and Quota rounds often use GPAX as an eligibility floor, not just a scored input.
Round 3 Admission blends GPAX with TGAT, TPAT or A-Level scores, weighted per faculty.
What GPAX measures
GPAX stands for grade point average, and in the Thai system it means your cumulative average across every subject you took in Mathayom 4, 5 and 6 (grades 10 to 12), not just your strongest subjects. Thai schools grade each subject on a 0 to 4 scale, where 4 means excellent and 0 means fail, and your GPAX is the credit-weighted average of every grade on your transcript. Subjects with more weekly class hours carry more credit units, so they count for a larger share of your final GPAX than a one-period elective.
Because it covers three full years, GPAX rewards consistent performance rather than a single strong exam sitting. A student who scores well every semester across science, math, Thai, English, social studies and elective subjects ends up with a higher GPAX than one who peaks only in a favorite subject, even if that student's best single grade is higher.
A simple example
Say you finish M6 with grades that average out, across all 6 semesters and every subject, to 3.42 on the 0 to 4 scale. That single number, 3.42, is your GPAX, and it stays fixed regardless of which faculty you apply to. What changes between faculties is how much weight they place on that 3.42 relative to your TGAT, TPAT or A-Level results, and whether they set a minimum GPAX you must clear before they look at anything else.
How many semesters count
If you apply while still completing M6, most programs count GPAX from the 5 semesters you have finished by application time, meaning M4 semesters 1 and 2, M5 semesters 1 and 2, and M6 semester 1. Your final semester's grades are not yet finalized when early TCAS rounds open, so they get left out of that calculation.
Once you graduate and hold a completed transcript, all 6 semesters count. This mainly affects applicants applying to Round 3 Admission or Round 4 Direct Admission after finishing school, versus those applying through the earlier Portfolio or Quota rounds while still enrolled. Confirm which count your target faculty asks for, since the exact requirement can vary by program.
Where GPAX shows up in each TCAS round
| Round | Typical role of GPAX |
|---|---|
| Round 1: Portfolio | Often an eligibility floor alongside your portfolio, rather than a scored input |
| Round 2: Quota | Commonly weighted directly, with the exact percentage set by each faculty |
| Round 3: Admission | Blended with TGAT, TPAT or A-Level scores using a weight formula each faculty publishes |
| Round 4: Direct Admission | Varies by university, since each sets its own criteria for remaining seats |
No single weighting formula applies across all of TCAS. A science faculty might weight GPAX at a small share of the total score and lean on TGAT/TPAT results, while a general education program might weight GPAX more heavily. Always read the specific faculty's admission announcement, published through mytcas.com , rather than assuming a standard formula.
Why some faculties set a GPAX floor
Test scores from a single sitting can swing on nerves, a hard question set, or an unlucky day. GPAX averages three years of school performance, so faculties treat it as a check on consistency rather than raw peak ability. A faculty that sets a minimum GPAX floor in its own admission announcement uses that floor to screen out applicants whose overall school record does not match a single strong test result, before it compares test scores between remaining applicants.
This is why two students with the same TGAT or TPAT score can end up with different outcomes at the same faculty. If one clears the GPAX floor and the other does not, the faculty may never compare their test scores at all, since the applicant below the floor gets screened out earlier in the process.
Common mistakes with GPAX
Assuming GPAX only reflects your major or strongest subjects. It covers every subject on your transcript.
Missing a faculty's minimum GPAX floor, which can disqualify an application before scores are even compared.
Confusing GPAX with a single semester's grades or a single subject's grade.
Not checking whether your target program uses 5 or 6 semesters, especially if you plan to apply before graduating.
How to check your own GPAX
Your school registrar's office issues an official transcript (ปพ.1) showing your GPAX to date, recalculated at the end of each semester. Request an updated copy before each TCAS round opens, since faculties compare the figure on your submitted transcript against their published requirement, not a self-reported number.
If your GPAX sits below a target faculty's floor, look at Round 2 Quota or Round 3 Admission programs at the same university with a lower published floor, or a program where the weight formula leans more heavily on TGAT, TPAT or A-Level scores instead of GPAX. A weak GPAX does not close off every path into a given university, only the specific programs that weight it heavily or set a high floor.