Calculating a Korean High School Grade Average: 9-Level vs. 5-Level Grading

A Korean high school report card (naesin) shows a grade for each subject, but the overall average usually has to be worked out yourself. Adding the grades and dividing by the number of subjects gives the wrong answer, because the average is weighted by each subject's credit units.

How the Average Is Calculated

Multiply each subject's grade by its units, add the results and divide by the total units. With Korean at grade 2 (4 units), math at grade 3 (4 units) and English at grade 1 (3 units): 2×4 + 3×4 + 1×3 = 23, divided by 11 units ≈ 2.09. A plain average would be 2.0, but math counts more because it has more units. One high-unit subject can lift or drag the whole average.

9-Level vs. 5-Level Grading

Students who entered high school up to 2024 are graded on a 9-level relative scale; from first-year students in 2025, a 5-level relative scale applies. "Grade 1" means quite different things under each.

Grade	9-level (cumulative share)	5-level (cumulative share)
1	Top 4%	Top 10%
2	11%	34%
3	23%	66%
4	40%	90%
5	60%	100%
6–9	77% · 89% · 96% · 100%	-

Grade 1 widened from the top 4% to the top 10%, so grades alone separate students less finely. Universities are therefore more likely to look at achievement levels, raw scores and teachers' written evaluations as well. Never mix 9-level and 5-level grades in one average.

Achievement Levels A–E Are Absolute

Grades depend on how you rank against classmates; achievement levels depend on whether you reach fixed score thresholds. Typically 90 or above is A, 80 or above B, 70 or above C, 60 or above D and below 60 E. Career-elective subjects that report only an achievement level are usually left out of the grade average.

Common Mistakes

The most common mistake is ignoring units. Others include converting achievement-only subjects into grades by guesswork and averaging years that use different grading systems. Also remember that a university may calculate differently: each sets which subjects count (for example Korean, English, math, social studies and science) and how each school year is weighted, so recalculate using the admission guidelines of the schools you are applying to.

Year Weights Change the Result

Suppose a student averaged 3.0 in the first year, 2.5 in the second and 2.0 in the third. Weighted equally, the average is 2.5. A university weighting the years 20:40:40 would calculate 3.0×0.2 + 2.5×0.4 + 2.0×0.4 = 2.4, which rewards an improving trend. Rounding rules differ between universities too.

What One Grade Is Worth

With 30 units in a semester, improving a 4-unit subject by one grade improves the average by 4 ÷ 30 ≈ 0.13, while the same improvement in a 2-unit subject is worth about 0.07. Within the subjects that count, high-unit subjects carry roughly twice the weight.

Raw Scores and Standard Deviation

Report cards also show raw scores, class averages and standard deviations. A grade 2 earned where scores are widely spread can mean something different from a grade 2 in a subject where everyone scored close together. Under the 5-level system these details are even more useful.

Keep a Semester Log

Record the subject, units, grade, raw score and achievement level after every semester. It makes recalculating easy, lets you compute averages for the subjects each university counts, and shows clearly which semester slipped and which high-unit subjects deserve more study time.

Enter each semester's subjects, units and grades in the Grade Calculator to get semester and overall averages automatically, and export the results to Excel for your records.