Why has everyone in South Korea become a year or two younger?

Like many, Kim Hae-yeon struggled to overturn the big 5-0. Unfortunately, you will have to do this twice.

“I’m 50,” she says, “but I’ll be 48 soon.”

Kim and the rest of South Korea were a year or two younger on Wednesday as a new national law took effect that ends the country’s unusual way of calculating age for a long time.

For centuries, Koreans have inflated their age compared to the rest of the world. A person is 1 year old at birth, and everyone gains a year on January 1st. A New Year’s baby turns two after just one day.

The new law brings everyone up to the international age standard, which starts people at zero on the day they are born. Koreans already born will become younger and use their date of birth to determine their age. Official documents will also begin to use the international measure.

Kim, a stay-at-home mom, will face 50 again in 2024.

Aging based on calendar years rather than birth dates is a holdover from the ancient culture of East Asian countries, which generally also considered time spent in the womb as part of age.

China and Japan rose to the global standard decades ago. South Korean President Yoon Suk Yeol, who took office last year, pledged to do the same during the election campaign.

“South Korea is getting younger,” the government said in a press release announcing the passage of the time-consuming bill.

The country’s giant age change has some wrinkles.

This complicates South Korea’s hierarchical society, in which age influences social status and, like other cultures, determines whether a more polite or informal version of language is used.

South Koreans nonchalantly ask even foreigners, “How old are you?” The question is so common that ahead of the 2018 Pyeongchang Winter Olympics, authorities explicitly advised locals not to ask the question to foreigners, who might find it rude.

“When kids meet on the playground, they first ask their age before their name,” says Sun Hyun-woo, founder of Talk to Me in Korean, a website that teaches the language online.

Lee Jin-soo was 15, but he will be 13 under the new law. At school, some of your classmates with whom you have shared ages for a long time will be 14 years old. They already ask Lee to address them by the honorary title “hyung,” or older brother.

“I’m upset because I have to wait until my birthday in October to be the same age as them,” he says.

According to guidelines issued by the South Korean Ministry of Education, students should not dwell on their newfound differences. “It may seem awkward at first,” adds the guide.

Kim Ji-soo, an office worker, turned 30 in January and will turn 29 under the change. He plans to continue giving off this older age in public as he feels it gives him more stature, especially at work where he felt some co-workers looked down on him for being twenty-something. “I’m going to keep 30,” he says.

But Park Jeong-yeon, also an office worker, is delighted to soon be able to “age” from 30 to 28 years old. This gives her more time to achieve her parents’ goal of getting married in her mid-thirties.

“There was always a sense of urgency when my parents told me I was getting too old to act like a girl,” Park says. “Well, now you’ll have to accept that I’m still two years in my twenties.”

To avoid gray areas, the new law establishes some exceptions. South Korea will maintain the old-age counting method to determine when children start primary school and when young people must pass a physical examination for conscription. And the legal drinking age of 20 will rise to 19, effectively remaining the same.

“Can people born in 2004 legally continue to drink? “The International Era,” Always Baffling,” shouted a recent news headline. (If you can).

Seeing the years roll back will be a relief for expats like Sasha Smirnova, who left Russia for Seoul in late 2021 when she was 30 and soon learned her Korean age was 32. says Smirnova, who works for an information technology company.

Some Koreans never learned how to calculate their overall age, prompting corporate promotions and a government campaign on how to do the calculations.

Eleven Street, an online retailer, has created a freebie for those using their “international age” calculator. The prizes are anti-aging products, including a $1,200 LG skincare device that stimulates collagen growth, and Estée Lauder Night Repair Cream.

Amusement park operator Lotte World said those with birthdays in June or July could receive discounted tickets to its theme parks after 2 p.m. The ad gushed: “Farewell to my old age!”