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Korean age: why South Koreans suddenly got younger

Until 2023, a Korean baby was born aged 1 and gained a year every January 1. The law changed, but age still shapes how people speak to each other.

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5 min read

A street of traditional Korean hanok houses in Seoul's Anguk neighbourhood, with city buildings in the distance
Photo by Elliot Gouy on Unsplash

On June 28, 2023, more than 51 million South Koreans became a year or two younger overnight. Nobody found an elixir. A law took effect requiring the country to officially count age the way most of the world does, instead of using the traditional Korean age.

To see how big a change that was, you need to know that South Korea used three different ways of counting age at the same time.

How Korean age worked

Under Korean age, a baby is born aged 1, because the time in the womb counts as the first year of life. And everyone gets a year older on January 1, not on their birthday. A baby born on December 31 turned 2 the next day.

There was also "year age", which starts at zero at birth but also adds a year every January 1. And there was international age, counted from zero and increased on each birthday, which was already used for medical and legal documents.

CNN used a famous example to show the confusion. The singer Psy, of "Gangnam Style", was born on December 31, 1977. In June 2023, he was 45 by international age, 46 by year age and 47 by Korean age.

What the 2023 law changed

The law passed in December 2022 amended the Framework Act on Public Administration and the Civil Act. Since June 28, 2023, unless a specific rule says otherwise, any age in laws, contracts and public documents means international age.

The Minister of Government Legislation, Lee Wan-kyu, explained the maths the day before: people who had already had their birthday that year became one year younger, and those who hadn't became two years younger. The goal was to end legal disputes and complaints over which age applied, for example to pensions and benefits.

South Korea was the last holdout. Japan dropped the traditional count from its legal system in 1950, and China stopped using it during the Cultural Revolution, according to the Korea Herald. Even North Korea got there first: it has officially used international age since the 1980s.

Where year age still applies

The change wasn't total. Some rules still use year age, according to the government. School entry, military service and buying alcohol and tobacco follow the year of birth, not the month.

In practice, someone born in January and someone born in December of the same year can buy alcohol from the same day: January 1 of the year they turn 19.

Why age matters so much in Korea

Age decides how people address each other. In Korean, how you speak to someone depends on who is older. Children learn early to call slightly older kids "big brother" or "big sister", even when they aren't related. A boy calls an older boy "hyeong" and an older girl "nuna". A girl uses "oppa" and "eonni". The word "chingu", friend, is reserved for people the same age.

With the new law, classmates who used to share the same Korean age suddenly had different ages. Schools and parents had to explain that this didn't turn a classmate into a "hyeong" or an "eonni", the Korea Herald reported.

Did the change stick?

Mostly, yes. In a survey by the Ministry of Government Legislation at the end of 2023, 95.8% of 22,226 respondents said they knew about the law, and 88.5% said they would use international age in daily life.

The old habit hasn't vanished, though. A mother interviewed by the site PenN Mike in 2024 said children's cram schools still group their classes by Korean age.

Practical tips

  • If a Korean asks your age, it isn't nosiness. The answer helps them work out how to address you.
  • If you're unsure which age to give, the official one is now international age, the same as in your passport.
  • To buy alcohol in Korea, the year of birth counts: from January 1 of the year you turn 19.

FAQ

What is Korean age?

It's the traditional system in which a person is born aged 1 and gains a year every January 1, regardless of their birthday.

Does South Korea still use Korean age?

Not officially. Since June 28, 2023, the legal age is international age. Some rules, such as school, military service, alcohol and tobacco, use age by year of birth.

How much younger did Koreans get?

One or two years, depending on whether they had already had their birthday that year.

Why do Koreans ask your age?

Because age determines how you're addressed in Korean, from the words used to call someone to how formal the conversation is.

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Sources

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