South Koreans will become at least a year younger tomorrow as the nation, which traditionally counts newborns as one year old, joins international standards.

As of Wednesday, all judicial and administrative areas in the country will begin using the international standard or calendar age, after the National Assembly announced the move last year. It’s intended to reduce confusion and to comply with global norms.

South Koreans are usually referred to as one to two years older than people elsewhere because the time spent in the womb is counted, the only major country that has the practice. The traditional counting system was largely used in social settings and in the workplace, where age hierarchies are considered important.

President Yoon Suk Yeol sought the change, widely backed by public opinion, when he ran for office last year.

South Koreans won’t need to update any documents or IDs since the age used for government forms is based on the international system, just like it is for retirement, receiving a pension and voting. Mandatory military service and school admissions follow calendar age which takes into account the year of birth.

And it’s not like rolling back the clock will suddenly cut young people off from alcohol and cigarette consumption, either. Stores use calendar age and not “Korean age” to ensure someone was over 19 years old.

“The key is when the kids are eligible to buy cigarettes,” said Gye Sang Hyuk, who’s run a convenience store just outside Seoul for 20 years. Clerks will still check the year of birth as usual, he said.

Three-quarters of Koreans wanted the change, according to a Hankook Research poll from January 2022.