Both the General Act on Public Administration and the Civil Act have been amended to streamline the calculation of a person's age in Korea. Starting from June 28, 2023, a person's age, in legal and administrative contexts, will be calculated based on the number of “full” (滿) years that have passed since their birth.
This means that the age mentioned in laws, regulations, contracts, and government communications will be determined by counting the full years, unless otherwise specified therein.
This change will provide clarity and consistency in age calculation, not only for Koreans but also for foreigners residing in Korea. In particular, it will facilitate filling out government forms and other documents in terms of age.
Despite the change in the laws, however, the Korean age may still be relevant in social, private, and unofficial settings in Korea.
For those who do not know, under the Korean age system, a person is considered to be one year old at birth and adds an additional year to their age on the Lunar New Year's Day, rather than on their individual birthdays.
We hope this information helps for your purposes. Should you have any question in this regard, please feel free to let us know.