A complete guide to converting Korean GPA to the US 4.0 scale
Updated 2026-08-24 · Reference information — every receiving institution publishes its own rule.
1. Why Korean grades do not map cleanly onto 4.0
Most Korean universities award grades on a 4.5 scale where A+ is 4.5 and A0 is 4.0, splitting the top band into two steps. Some schools — Yonsei and KAIST among them — use a 4.3 scale where A+ is 4.3, A0 is 4.0 and B+ is 3.3, which mirrors the spacing of the American plus/minus system. The US 4.0 scale, by contrast, usually treats every A as exactly 4.0 and has no reward above it.
The gap between the top of one scale and the top of another is where every disagreement starts. A student with a perfect 4.5 and a student with straight A0s both look like a 4.0 to a US reader, while a mechanical division by 4.5 pushes the perfect student down. There is no arithmetic that fixes this, only conventions — and that is exactly why different institutions publish different tables.
2. The three methods this tool offers
Simple proportional scaling
target = score ÷ source max × target max. A 3.5/4.5 becomes 3.11/4.0. It is the method most students reach for and the one most résumé screeners assume, but it silently assumes that the two scales are stretched versions of each other. They are not: a Korean B+ sits at 3.5 out of 4.5 (77.8% of the scale) while an American B+ sits at 3.3 out of 4.0 (82.5%).
Letter-grade band mapping
Instead of dividing, this method anchors on letters. A Korean B+ is a B+, so 3.5/4.5 maps to 3.3/4.0. Scores between two letters are interpolated proportionally, so a 3.75 sits halfway between B+ and A0. This is closer to how a credential evaluator reads a transcript, because evaluators re-grade course by course rather than rescaling a single number.
The GKS conversion table
The Global Korea Scholarship application guidelines publish a grade conversion table that runs 0.05 grade points per percentage point: 100% is full marks, 90% is 4.0 on the 4.5 scale, 80% is 3.5, and so on down to 60%. Because it is a published table rather than a derivation, it is the right choice whenever you are filling in a GKS form — and the wrong choice everywhere else.
3. How much does the method actually change your number?
Take 3.5/4.5. Proportional scaling gives 3.11, band mapping gives 3.30, the GKS table gives 3.00. That is a spread of 0.30 grade points on the same transcript — enough to move an applicant across the 3.0 line that many master's programs quote as their documented minimum. The higher your GPA, the wider the spread tends to be, because the A+ band is where the scales disagree most.
4. What WES and other credential evaluators do
WES, Scholaro, ECE and similar agencies do not convert your cumulative GPA. They take each course, assign a US letter grade using their own country-specific rules, weight it by credit hours, and average the result. Two consequences follow. First, a course-level pattern matters: many A+ grades in low-credit electives will not lift an evaluated GPA the way a single-number conversion suggests. Second, the result routinely lands 0.1 to 0.4 away from any shortcut you compute at home.
If a program requires an official evaluation, the agency's number is the one that counts, and it arrives weeks after you order it. Plan for that lead time rather than for the number you calculated.
5. Checklist before you write a number on an application
- Read the application instructions first — many US programs say "report your GPA as it appears on your transcript, do not convert".
- If a conversion is required, note which method the program names, and use that one.
- Check whether your transcript already prints a percentage or a US-equivalent GPA; if it does, use that value.
- Never round upward. If your converted figure is 3.28, write 3.28, not 3.3.
- Keep the source scale visible: "3.72 / 4.5" communicates far more than a bare "3.72".
- If an official evaluation is required, order it early and let the agency's number override yours.