Of Korean Age

Everybody ages as years passed by, there's no denying to that. However, ages in Korea are calculated differently than any other parts of the world. According to Korean Age: All About Age in Korea, the nine months spent in the womb is already considered as one year. Therefore, a baby's first day in the world is considered as his one year anniversary in Korea. Those who were born in 1989 should be 30 years old in 2019, however, for the Koreans, they are already 31 years old! The simplest formula to this would be:

1 + Current year – Year of Birth = Korean Age

For example:

1 + 2017 – 1990 = 28

So, it breaks my heart to admit that I'm indeed 31 years old in Korea 😓😓😓

As for the school kids, they are; 

Elementary School:

Grade One - Eight years old

Grade Two - Nine years old

Grade Three - Ten years old

Grade Four - Eleven years old

Grade Five - Twelve years old

Grade Six - Thirteen years old

Middle School:

Grade One - Fourteen years old

Grade Two - Fifteen years old

Grade Three - Sixteen years old

High School:

Grade One - Seventeen years old

Grade Two - Eighteen years old

Grade Three - Nineteen years old

reference: https://www.90daykorean.com/korean-age-all-about-age-in-korea/