South Koreans have instantly become a year or two younger.
It follows new laws requiring the use of the internationally recognised way of counting age taking effect on Wednesday.
It replaces one of the country’s two traditional methods, where people are deemed to be a year old at birth – taking into account time spent in the womb.
The “Korean age” system also sees people ageing up by a year on 1 January every year, instead of on their actual birth date.
It means someone born on New Year’s Eve would turn two years old on New Year’s Day.
The other traditional method – or “counting age” – considers a person zero at birth but their age goes up a year every 1 January.
This method means someone born on New Year’s Eve would turn one on New Year’s Day.
The “counting age” method will still remain in place with many laws still using it – for instance, people in South Korea can buy alcohol from the year – and not the day – they turn 19.
Nonetheless, the law change could mean that South Koreans have years knocked off their ages on official documents.
‘It’s just great to feel like getting younger’
Since the early 1960s, the country has used the international norm of calculating from zero at birth and adding a year on every birthday for medical and legal documents.
But many South Koreans continued to use the traditional method for everything else.
In a briefing on Monday, minister of government legislation Lee Wan-kyu said: “We expect legal disputes, complaints and social confusion that have been caused over how to calculate ages will be greatly reduced.”
A government survey which was conducted in September last year revealed that 86% of South Koreans said they would use the international age system in their everyday life when the new laws takes effect.
“I was about to turn 30 next year [under the traditional Korean age system], but now I have some more time earned, and I love it,” Choi Hyun-ji, a 27-year-old office worker in Seoul, told the Reuters News agency.
“It’s just great to feel like getting younger,” Mr Choi added.
What’s my Korean age?
According to 90 Day Korean – a website on the Korean language and culture – there is a simple way to get that answer.
One of the ways you can do this is by adding one year to the current year and then subtracting that from your year of birth.
For example, 2023 +1 – 1997 = 27 years of age.