Short answer
Traditional Korean age gives a newborn age 1 and adds a year on every 1 January, so people are one or two years older than their international age. South Korea adopted international age for most legal and administrative purposes from 28 June 2023.
1. The two systems
| International age | Traditional Korean age | |
|---|---|---|
| Age at birth | 0 | 1 |
| Increases | On the birthday | Every 1 January |
| Compared with the other | Base | 1 to 2 years older |
2. Example
A baby born on 30 December is 1 at birth under Korean age and turns 2 two days later on 1 January, while their international age is still 0.
3. The 2023 change
A law took effect on 28 June 2023 so that international age is used for most legal and administrative purposes in South Korea. Traditional Korean age can still be heard in everyday talk.
4. Which to use
- Forms and official documents: international age.
- Cultural context in Korea: ask which system is meant.
The Age Calculator uses international age (completed years). For how it is calculated see calculating age from date of birth.
5. Frequently asked questions
How is Korean age calculated?expand_more
Add one to your international age, plus one more if your birthday has not yet happened this calendar year.
Why is Korean age 1 or 2 years higher?expand_more
A newborn is age 1 at birth, and everyone gains a year every 1 January rather than on their birthday.
Is Korean age still used?expand_more
South Korea moved to international age for most legal and administrative purposes on 28 June 2023, but the older system is still used informally.
Which age should I put on a form?expand_more
Use international age unless the form says otherwise.