Age Calculator
• Age increases on birthday
• Legal age in South Korea (unified since June 2023)
• Standard age used internationally
Korean Age (Traditional):
• Born at age 1
• Age increases on January 1st
• No longer officially used
Year Age:
• Current year - Birth year
• Calculated regardless of birthday
Since June 28, 2023:
South Korea has unified to use international age as the legal standard.
History and Changes in Korean Age Calculation System
Korea has long used a unique age calculation method. Traditional Korean age started at 1 year old immediately upon birth, with everyone aging one year on January 1st. This originated from traditional time concepts based on the lunar calendar, with cultural background viewing time in the mother's womb as the beginning of life.
While convenient in daily life, this Korean age calculation caused much confusion as international exchanges increased. People born on the same day could differ by up to 2 years between Korean age and international age, causing problems in legal documents and official records.
On June 28, 2023, South Korea made a historic decision. They unified the legal age standard to use international age officially. This was a measure to align with international standards, reduce legal confusion, and increase administrative efficiency.
Though international age is now officially used in Korea, Korean age is still commonly used in daily life. Particularly older generations tend to prefer Korean age due to long-standing customs. Therefore, understanding both age calculation methods and using them appropriately is important.
Age unification goes beyond simply changing the age calculation method - it's part of Korea's process of building a more transparent and efficient administrative system aligned with international standards.
International Age Calculation Method and Real-Life Application
International age is the most widely used age calculation method globally. Starting at 0 years old on the day of birth, age increases by one year on each birthday. For example, a child born on March 15, 2020 remains 2 years old until March 14, 2023, turning 3 years old on March 15th.
The key to international age calculation is using the exact birthday as reference. Subtract birth year from current year, then adjust based on whether the birthday has passed. If the birthday hasn't passed yet, subtract 1. This method accurately reflects biological age.
After international age became the legal standard in Korea, various laws and systems changed. Notably, Military Service Act, Youth Protection Act, and laws regarding drinking and smoking now apply based on international age. For example, drinking and smoking are permitted from age 19, applied precisely based on birthdays.
School enrollment age also uses international age. Generally, children enroll in elementary school in March of the year they turn 6. Early enrollment or deferment applications also use international age as criteria.
International age is also important in workplace life. Age limits in job postings, retirement age, and promotion criteria all apply based on international age. When writing resumes, stating international age is standard.
Insurance enrollment and financial product use also use international age as the standard. Car insurance premiums, life insurance enrollment conditions, and pension receipt timing all calculate based on international age, making accurate knowledge of international age important for financial planning.
Differences Between Korean Age and Year Age
Korean age is a unique method starting at 1 year old at birth, with everyone aging one year on January 1st. This means all people age simultaneously when the new year arrives, regardless of birthdays. For example, a baby born on December 31st becomes 2 years old the next day, January 1st.
This Korean age is closely related to community culture. It stems from Confucian culture that groups people born in the same year as "same age" to form solidarity and clarify age-based hierarchy. This is why "What year were you born?" is frequently asked in Korean society.
Year age is simply current year minus birth year. It's the simplest method as it only calculates years without considering birthdays. For example, all people born in 1990 are 35 years old (year age) in 2025. Year age is mainly used in statistics and surveys, useful for grasping approximate age groups.
Understanding differences among the three age calculation methods avoids confusion. International age represents the most accurate biological age, Korean age represents social and cultural age, and year age represents statistical age.
While Korea officially uses international age, daily conversation still frequently uses Korean age or "what year born" expressions. Therefore, selecting appropriate age expressions for each situation is important. Official documents and legal procedures must use international age, while conversations with friends can use whichever method they understand more easily.
Using an age calculator allows checking all three ages at once, enabling accurate knowledge of appropriate age for each situation. Particularly when living abroad or conducting international business, accurately knowing international age is essential.
Birthday-Related Date Calculations
Along with age calculation, calculating various dates related to birthdays is important. Calculating days until the next birthday helps with birthday preparation and planning. Additionally, calculating days lived enables meaningful time to reflect on one's life and plan ahead.
Days lived means the exact number of days from birth to today. This goes beyond simply age to concretely show how many days have actually been experienced. For example, 30 years old equals approximately 10,950 days lived - an accumulation of very many individual days.
Calculating weeks or months lived is also useful. Particularly when recording baby growth, months are important. Expressions like "6 months old" or "18 months" are important indicators of baby developmental stages. Pediatric checkups and vaccination schedules are also set based on months.
Knowing days until the next birthday enables planning birthday parties or events. Also, preparing special birthdays (e.g., 100 days, 1st birthday, 60th birthday) requires accurate date calculation. In Korean culture, specific dates carry special meaning, making accurate date calculation even more important.
Knowing birth day of week is also interesting. Many people don't know which day of the week they were born on, but can easily check using an age calculator. Some cultures believe personality or destiny differs based on birth day of week.
Commemorating special days is also meaningful. For example, the day reaching 10,000 days lived is called "10,000 days" and sometimes celebrated. Calculating and commemorating such special days creates meaningful milestones in life.
Age Standards in Laws and Systems
Age becomes the standard for many laws and systems. After 2023 age unification, most laws apply based on international age. The most representative is the standard for adulthood. In Korea, turning 19 years old grants legal rights and responsibilities as an adult.
Drinking and smoking are permitted from age 19. This applies precisely based on birthdays, so people born in the same year may have different times when drinking and smoking become permitted depending on birthdays. Convenience stores and bars also check ID based on international age.
Driver's license acquisition age also uses international age as standard. Class 2 ordinary license from age 18, Class 1 ordinary license from age 19. Large vehicle or special licenses have higher age restrictions.
Military service obligation involves military service examination in the year turning 18, with conscription eligibility from age 19. Military service deferment or exemption criteria also apply based on international age. Military service obligation must be fulfilled by age 35, after which one is transferred to second national service.
Youth Protection Act defines those under 19 as youth, stipulating various protective measures. Youth employment restrictions, harmful media access restrictions, and late-night entry restrictions all apply based on international age.
National pension receipt start age also uses international age as standard. Currently receivable from age 63, with gradual increases planned. Early or delayed receipt can be chosen, but also based on international age.
Retirement age is also calculated using international age. Generally age 60 is retirement, but may differ by company or occupation. For civil servants, retirement age varies by rank.
Relationship Between Education and Age
In Korea's education system, age is a very important standard. Elementary school enrollment occurs on March 1st of the year turning 6 years old. This is why January and December births become the same grade. This is a practical standard for conducting education by grade level.
Early enrollment system allows enrollment at age 5, but requires strict conditions. Must pass intelligence tests, physical exams, social skills evaluations, and receive education office approval. Conversely, enrollment deferment can be requested to enroll one year late.
Middle and high school advancement also closely relates to age. Compulsory education period (6 years elementary, 3 years middle) is legally mandated, during which students must continue studies. After compulsory education ends, high school or vocational education can be selectively pursued.
University admission has no explicit age limit, but most students enter at ages 18-19. Those retaking entrance exams may be older, with some entering university after becoming adults. In university, grade level is a more important standard than age.
Academies and tutoring are also organized by age group. Especially infant education is finely divided by months. Divided into under 24 months, 24-36 months, 36-48 months, etc., providing education matching developmental stages.
In special or arts/sports education, age may be even more important. Piano competitions, art contests, and sports competitions divide by age category to ensure fair competition. Some fields benefit from early education start, while others benefit from starting at appropriate age.
With emphasis on lifelong learning importance, environments enabling learning regardless of age are being created. Through cyber universities, academic credit banks, and lifelong learning centers, adults can obtain degrees or learn new skills even after adulthood.