Korean Age FAQ

Korean age starts at 1 at birth and increases by 1 every January 1st, regardless of birthday. International age starts at 0 and increases on each birthday. If you were born on December 31, 2000, on June 1, 2026 your Korean age is 27 but your international age is only 25.

On June 28, 2023, Korea amended its Civil Code and Framework Act on Administration to standardize official age calculations to international age (만나이). Hospitals, contracts, official documents, and government forms now use international age. Daily conversation, however, still commonly uses Korean age (세는나이).

Year age (연나이) is simply current year minus birth year, with no regard for whether the birthday has passed. It is used in specific legal contexts such as the Youth Protection Act and military conscription scheduling. For most other purposes, international age is now the standard.

In Korean law, people born on February 29 have their birthday treated as February 28 in non-leap years. This is the standard administrative interpretation under Korean civil law.

Add 1 to your international age if your birthday has already passed this year. Add 2 if your birthday has not yet come this year. For example, if you are 29 internationally and your birthday was 3 months ago, your Korean age is 30.

Since the 2023 reform, use international age (만나이) on all official Korean forms unless specifically asked for Korean age. When in doubt, write both and clarify: e.g., "만 29세 (세는나이 31세)".

Your zodiac (띠) follows a 12-year cycle: Rat (1900, 1912, ..., 1996, 2008, 2020), Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, Pig. Use our calculator — enter your birthdate and the zodiac is shown automatically. Technically the zodiac year starts at Lunar New Year, but modern Korean convention uses January 1st.