Three ages, one birth date
Korea has used three different ways of counting age. Enter a birth date and a reference date to see all of them at once.
| Age | How it is counted | Where you still see it |
|---|---|---|
| International age (만 나이) | years since birth, minus 1 if this year’s birthday hasn’t come yet | Official age in Korea since June 28, 2023 — laws, contracts, hospitals, government forms |
| Korean counting age (세는 나이) | this year − birth year + 1 (you are 1 at birth, and everyone turns a year older on January 1) | Everyday conversation among older people; no longer used officially |
| Year age (연 나이) | this year − birth year | Still used by a few laws, such as the age limit for buying alcohol and tobacco and military service |
Did Korea drop "Korean age"?
Yes. From June 28, 2023, the Framework Act on Public Administration and the Civil Act made international age the default for laws, contracts and official documents. That is why your Korean coworker might say they are "two years older" in conversation while their ID-based age matches yours. If someone in Korea asks your age, international age is the safe answer; Korean counting age is mostly a cultural leftover now.
Why the numbers differ by one or two
- Someone born on December 31 is 1 in Korean counting age on day one and turns 2 the next morning (January 1), while their international age is still 0.
- Year age ignores the birthday entirely, so it equals international age after your birthday and is one higher before it.
- International age depends only on whether this year’s birthday has passed, which the tool checks for you.
Extras
- Zodiac animal (띠) from the birth year. Koreans traditionally switch zodiac years at the Lunar New Year (Seollal), so if you were born in January or early February, your animal may be the previous year’s.
- Days until your next birthday and total days lived.
Your birth date is never uploaded — everything runs in your browser. To count days to a visa expiry or another deadline, use the Date & D-Day Calculator.