How Korean Age Calculator works
Your traditional Korean age is the current year minus your birth year, plus one. Someone born in 2000 is therefore 27 in Korean age for the whole of 2026, whatever month their birthday falls in. This calculator shows that figure next to the two other ages used in South Korea: international age (만 나이), which counts completed years since birth and has been the legal standard since 28 June 2023, and year age (연 나이), which is simply the current year minus the birth year. You can also set the reference date to check any past or future year.
Korean age by birth year in 2026
Results from the calculator with the reference date set to 8 October 2026. Korean age and year age hold for all of 2026. International age is shown before and after the 2026 birthday.
| Birth year | Korean age (세는 나이) | Year age (연 나이) | International age (만 나이) |
|---|---|---|---|
| 2026 | 1 | 0 | 0 |
| 2025 | 2 | 1 | 0 before birthday, 1 after |
| 2008 | 19 | 18 | 17 before birthday, 18 after |
| 2007 | 20 | 19 | 18 before birthday, 19 after |
| 2004 | 23 | 22 | 21 before birthday, 22 after |
| 2000 | 27 | 26 | 25 before birthday, 26 after |
| 1997 | 30 | 29 | 28 before birthday, 29 after |
| 1995 | 32 | 31 | 30 before birthday, 31 after |
| 1990 | 37 | 36 | 35 before birthday, 36 after |
| 1988 | 39 | 38 | 37 before birthday, 38 after |
For any other birth year in 2026: Korean age = 2027 minus the birth year, and year age = 2026 minus the birth year.
Korean age formula
Korean age = current year - birth year + 1 Year age = current year - birth year International age = year age, minus 1 if this year's birthday has not happened yet
Take a birth date of 9 October 1995 and a reference date of 8 October 2026. Korean age is 2026 - 1995 + 1 = 32. Year age is 2026 - 1995 = 31. The birthday is one day away, so international age is 31 - 1 = 30. If you only know your international age, add 1 after your birthday or 2 before it to get Korean age. Going the other way, subtract 1 or 2 from a Korean age to estimate the international one.
Worked examples from the calculator
Birthday already passed this year
Date of birth 1 September 1997, Calculate as of 8 October 2026
International age 29, Korean age 30, year age 29
After the birthday, international age and year age match and Korean age is one higher.
Birthday still to come this year
Date of birth 30 November 2007, Calculate as of 8 October 2026
International age 18, Korean age 20, year age 19
Before the birthday all three ages differ, and Korean age is two higher than international age.
Born on New Year's Eve
Date of birth 31 December 2025, Calculate as of 1 January 2026
International age 0, Korean age 2, year age 1
The largest possible gap: a one-day-old baby is already 2 in traditional Korean age.
Checking an age in a past year
Date of birth 1 September 1997, Calculate as of 1 June 2019
International age 21, Korean age 23, year age 22
Useful for working out what an age quoted in an older interview or drama meant internationally.
Leap day birthday
Date of birth 29 February 1988, Calculate as of 8 October 2026
International age 38, Korean age 39, year age 38
What changed in June 2023
On 28 June 2023 South Korea made international age (만 나이) the single standard for civil and administrative matters. Contracts, official documents, medical guidance and government paperwork that state an age now mean completed years since birth, the same way age is counted in most other countries. Because of the change, most South Koreans became one or two years younger on paper overnight.
The law did not abolish every other way of counting. Year age (연 나이) is still written into a few specific laws because it is easier to administer: everyone born in the same calendar year crosses the threshold on the same day. Under the Youth Protection Act a person may buy alcohol and tobacco from 1 January of the year in which they turn 19, and the Military Service Act also counts by calendar year. School entry is likewise organised by birth year.
Traditional Korean age (세는 나이) has no legal force, but it has not disappeared from daily life. People who grew up with it often still give that number in casual conversation, and ages quoted in older interviews, dramas and articles usually use it.
When each Korean age is used
- International age (만 나이): legal documents, contracts, medical records and official forms since June 2023.
- Year age (연 나이): buying alcohol and tobacco, military service, and other rules that apply to everyone born in the same calendar year.
- Korean age (세는 나이): informal conversation, especially among older generations, and most age references in Korean media from before 2023.
- Birth year itself: Koreans often ask which year you were born in rather than your age, because people born in the same year are treated as the same age (동갑, donggap) whichever system is used.
Why Korean age starts at 1
The traditional system comes from an East Asian way of counting age that was once shared with China, Japan and Vietnam. A child is counted as being in its first year from the day of birth, so there is no age zero, and age then advances with the calendar year rather than with the individual birthday. One common explanation is that the months spent in the womb are counted as part of the first year.
Because the count follows the calendar, everyone born in the same year is always the same Korean age. That fits a society where the words you use for another person depend on whether they are older, younger or the same age as you. It is also why two people with nearly a year between their birthdays can be the same Korean age, while two people born a day apart, on 31 December and 1 January, are a full year apart.
Step by step
- 1
Enter your Date of birth. The full date matters, because international age depends on whether your birthday has passed.
- 2
Leave Calculate as of on today's date, or change it to any other date to see the ages on that day.
- 3
Read the three results: International age (만 나이), Korean age (세는 나이) and Year age (연 나이).
- 4
Copy the Summary line if you want all three ages and both dates in one sentence.