Korean Age Calculator
Work out international age, the traditional Korean counting age and the year age used in some Korean laws, from a date of birth.
Result
International age: 25 years
International age has been South Korea’s legal default since 28 June 2023. Counting age is still common in conversation.
- Counting age (traditional Korean age)
- 27
- Year age (yeon-nai)
- 26
- Difference
- Counting age is 2 more than international age on this date
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How to use the Korean Age Calculator
- Enter the date of birth.
- Enter the date you want the age on. It starts on a fixed date, so change it to today or any other day.
- Read the international age, the traditional counting age and the year age side by side.
Three ways to count
The same person has up to three ages in Korea. The page works out each one from the two dates, using only whole years.
international age full years since the date of birthcounting age year of the date − year of birth + 1year age year of the date − year of birthInternational age goes up on the birthday. Counting age and year age go up on 1 January for everyone born in the same year. So counting age is always year age plus one, and both are ahead of international age until the birthday comes around.
Which one to use
For forms, contracts, medical records and anything official in South Korea, use international age. That has been the law since June 2023. Use year age where a rule is set by birth year, such as school year groups or the age limits for buying alcohol. Counting age is what older relatives may still quote, and the one most people mean when they ask how old someone is in Korean years.
With your numbers
- International age: full years completed since the date of birth
- Counting age: 1 at birth, plus one every 1 January, so it is the year minus the birth year plus 1
- Year age: the year minus the birth year, whatever the birthday
Quick reference
International age has been South Korea’s legal default since 28 June 2023. Counting age is still common in conversation.
| Example | International age |
|---|---|
| Born 20 November 2000 | 25 |
| Born 1 January 2000 | 26 |
| Born 31 December 2025 | 0 |
| Born 15 March 1990 | 36 |
| Born 4 October 2007 | 19 |
| Born today | 0 |
Common questions about the Korean Age Calculator
- What is Korean age?
- Traditionally a Korean baby was one year old at birth and everyone became a year older together on 1 January. That counting age is what people mean by Korean age. It is the calendar year minus the birth year plus one, so it is one or two more than the international age, depending on whether the birthday has passed.
- Is Korean age still used?
- Not in law. Amendments to South Korea's Civil Act and Framework Act on Public Administration made international age, man-nai, the default for laws, contracts and official documents from 28 June 2023. Counting age is still common in conversation and when people work out how to address each other.
- What is year age?
- The current year minus the birth year, with no plus one and no birthday. A few Korean laws kept it after 2023, including the rules on when young people may buy alcohol and tobacco and the year of conscription, because they apply to everyone born in the same year at once.
- Why can someone born in late December be two in January?
- In counting age a baby is one at birth and turns two on the next 1 January. A baby born on 31 December is therefore two the following day, while its international age is still zero.
- Did other countries count age this way?
- Yes. China, Japan and Vietnam all used forms of East Asian age reckoning. Japan made international age the legal standard in 1950 and China uses it officially, though the traditional count survives in some customs. South Korea was the last to keep it widely in daily life.