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calcthai.com · GPA Calculator (Thai Grading System)
General & conversion
GPA Calculator (Thai Grading System)
Work out a GPA from credits and grades on the Thai A to F scale, add your previous GPAX for the cumulative average, and check the honours thresholds.
Reference thresholds — each institution sets its own
| Threshold | GPAX required | Your status |
|---|---|---|
| First class honours | 3.50 and above | Met |
| Second class honours | 3.25 and above | Met |
| Standard graduation requirement | 2.00 and above | Met |
| Below requirement, dismissal possible | Below 2.00 | Not yet |
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Thai institutions grade on a 4.0 scale with half-step grades — A, B+, B, C+, C, D+, D and F — which differs from the letter scales used in many other countries by including the plus grades at 0.5 intervals but no minus grades.
Two terms come up constantly and are worth distinguishing: GPA is the average for a single term, while GPAX is the cumulative average across everything you have studied. Admissions and employers almost always mean GPAX.
How it works
The calculation. Multiply the credits for each course by the point value of its grade, add those products together, and divide by the total credits. Credits act as weights, so a 3-credit course influences the average three times as much as a 1-credit course.
The Thai point scale: A = 4.0, B+ = 3.5, B = 3.0, C+ = 2.5, C = 2.0, D+ = 1.5, D = 1.0, F = 0.
GPA against GPAX. GPA covers one term. GPAX weights every term together by credits, which is why a single weak term matters less once you have accumulated a lot of credits — and why an early weak term is harder to recover from than a later one.
Failed courses still count. An F contributes 0 points while still adding to your credit total, which is what makes a single F so damaging to an average. Many institutions allow a retake, but rules on whether the original grade is replaced or both are counted vary considerably.
Honours thresholds. As a general reference, first class honours usually requires a GPAX of 3.50 and second class 3.25, with 2.00 the normal minimum to graduate. Institutions set their own rules though, and many add conditions beyond the average — a maximum number of years to complete, no failed courses, or no repeated courses. Check your own institution’s regulations rather than relying on the general figures.
Frequently asked questions
What is the difference between GPA and GPAX?
GPA is the average for a single term. GPAX is the cumulative average across every term, weighted by credits. When a university or employer in Thailand asks for your grades, they almost always mean GPAX.
How does the Thai grading scale compare to others?
It runs 0 to 4.0 like the American scale, but uses half-step plus grades — B+ at 3.5, C+ at 2.5 — and has no minus grades. So there is no B− at 2.7; the step below B is C+ at 2.5. This makes each grade boundary matter more than on scales with both plus and minus.
How much does one F hurt?
Considerably, because it adds credits to the denominator while contributing zero points. A 3-credit F alongside 15 credits of A drops an average from 4.00 to 3.33. Most institutions permit retakes, but whether the original grade is replaced or both are counted varies, so check your regulations.
What GPAX do I need for honours?
Commonly 3.50 for first class and 3.25 for second class, with 2.00 the usual minimum to graduate. These are general references only. Institutions set their own thresholds and frequently add conditions such as completing within a maximum number of years, or having no failed or repeated courses.
Sources
Rates last verified 25 Aug 2026