Which system applies
Korean high schools grade each subject by class rank, and the scale depends on when the student started high school. Students who entered Grade 10 in 2025 or later (2022 national curriculum) use 5 grades; students who entered in 2024 or earlier (2015 curriculum) use 9 grades. Grade 1 is the best.
| Grade | 5-grade cumulative % | 9-grade cumulative % |
|---|---|---|
| 1 | up to 10% | up to 4% |
| 2 | up to 34% | up to 11% |
| 3 | up to 66% | up to 23% |
| 4 | up to 90% | up to 40% |
| 5 | 100% | up to 60% |
| 6–9 | — | 77% / 89% / 96% / 100% |
The number of students in each band is class size × cumulative %, rounded. Under the 9-grade system a class of 12 gives 12 × 4% = 0.48, which rounds to 0, so nobody gets a grade 1.
How ties are handled
Tied students all share the highest rank. When a tied group straddles a grade boundary, the school computes the mid rank = rank + (number tied − 1) ÷ 2, divides it by class size and grades the whole group on that percentile. The official guideline’s examples come out the same here:
- 5 grades, 96 students, 19 tied for 1st: mid rank 10 → 10.42% → all get grade 2
- 5 grades, 120 students, 15 tied for 2nd: mid rank 9 → 7.5% → all get grade 1
- 9 grades, 130 students, 6 tied for 2nd: mid rank 4.5 → 3.46% → all get grade 1
Worked example
Rank 20 of 250 with no tie is the 8th percentile.
- 5 grades: grade 1 covers 250 × 10% = 25 students → grade 1
- 9 grades: grade 1 covers 10 students (4%) and grade 2 runs to 28 (11% = 27.5, rounded up) → grade 2
The average is Σ(grade × units) ÷ Σ units. Korean 4 units grade 2, Math 4 units grade 3, English 4 units grade 1, Korean history 3 units grade 2, Social studies 4 units grade 4 and Science 4 units grade 3 give (8 + 12 + 4 + 6 + 16 + 12) ÷ 23 = 2.52.
Tips for parents and international families
- Schools apply their own tie-break rules first; the mid-rank rule only covers ties that remain. Copy the rank and the number tied from the report card.
- Leave out subjects that only get an achievement level (PE, arts, science lab).
- Universities weight years and subjects differently, so their converted score can differ from this plain average.
- Your subject list is saved only in this browser. For university GPA use the GPA calculator.