What is the Korean age system?

In the traditional Korean age system, a person is considered 1 year old at birth (recognizing the time spent in the womb). Then, everyone ages by 1 year on January 1st (New Year's Day), not on their individual birthday. This means a Korean person's traditional age is typically 1–2 years older than their international age.

How many days old am I?

To calculate how many days old you are, enter your birth date in the calculator above. The result will show your exact age in years, months, and days, as well as the total number of days since your birth.

Age Calculator — Western Age vs Korean Age System Explained

Q: Did Korea change its age system?

Yes. South Korea officially standardized to the international age-counting system (만 나이, 'man nai') in June 2023. Legal documents, medical records, and government services now use the international system. However, traditional Korean age (세는 나이) is still widely used in everyday conversation and culture.

Age Calculator

Calculate your exact age and compare it across age systems. Did you know Koreans traditionally count age differently — and that South Korea officially changed its age system in 2023?

Quick Answer

Korean traditional age = international age + 1 (or +2 if born after Jan 1 of your birth year). South Korea standardized to international age (만 나이 / Man Age) on June 28, 2023. Before that date, Koreans were legally 1–2 years older than their international age.

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The Three Korean Age Systems

Korea traditionally had three different ways of counting age simultaneously:

1. 세는 나이 (Seneun Nai) — Traditional Korean Age

The traditional system where everyone is born at age 1 (counting the time in the womb as the first year of life) and everyone increases their age on January 1st, not on their birthday.

Example: A baby born on December 31st becomes 2 years old the very next day (January 1st).

2. 만 나이 (Man Nai) — International/Legal Age

The same as the Western international system: age increases on the birthday, starting from 0 at birth. Since June 2023, this is the official legal standard in South Korea for all government and medical purposes.

3. 연 나이 (Yeon Nai) — Year Age

Simply the current year minus the birth year, regardless of whether the birthday has passed that year. Often used informally and for calculating age groups.

System	Age at Birth	Ages By	Used In
Western / International	0	Birthday	Most countries worldwide
Korean Traditional (세는 나이)	1	January 1st	Korea (cultural/informal)
Korean Man Age (만 나이)	0	Birthday	Korea (official since 2023)
Chinese Traditional (虚岁)	1	Chinese New Year	China (historical)

Why Did Korea Change Its Age System?

In June 2023, South Korea enacted a law standardizing the international age system for all official uses. The reasons were largely practical:

Legal confusion: Insurance policies, contracts, and medical records used different systems.
Medical issues: Drug dosages and eligibility criteria were being misapplied.
Administrative burden: Government services had to maintain multiple age calculations.
International alignment: Korea is deeply integrated in global business and needed a universal standard.