In this Korean age calculator, simply enter your birth year. By default, the calculator will calculate your age as of today, but you can change this to another year.
South Koreans, when giving their age to foreigners, typically give two numbers. One is their "international age," which is the number of years since they were born, and the other is their "Korean age," which could add one or two years.
In Korea, people are considered to be one year old on the day they are born, and they add a year to their age every January 1. This applies event to infants born on December 31, who would be considered to be 2 years old the next day.
The birth year, not the date of birth, determines someone's age.
The Korean age formula is:
Similar age-counting methods were previously used in other East Asian countries (China, Korea, Japan, Vietnam, Mongolia, etc.), but South Korean and Taiwan are the only countries today that still use this method.
The method originated in China a millennia ago, where people are considered to be one year old at birth, and on the New Year Day of the lunar calendar, another year is added. The Korean age differs in that it is based on the Gregorian calendar, in which a year is from January 1 to December 31, rather than the lunar calendar.
In South Korea, the traditional Korean age is used in everyday life, but their legal age is usually based on the international calculation. However, for certain laws, such as age limits for movies, the Korean age is used.