Korean Age vs International Age: The 2023 Reform Explained

For most of Korea's modern history, Koreans have used a unique age-counting system that makes almost every Korean one or two years older than their international age. In June 2023, the Korean government enacted a legal reform standardizing official age to the international system. Understanding what changed, what stayed the same, and why the distinction still matters in everyday life requires more than a headline summary.

Age

How the Korean Counting Age Worked

The traditional Korean age system (한국식 나이 or 세는 나이) had two distinctive features:

1. Born at age 1: A baby is considered one year old at birth. This reflects a traditional belief, common across several East Asian cultures, that the period in the womb counts as a year of life. Some scholars also attribute it to the practical difficulty of counting years inclusively in classical Chinese calendrical systems.

2. Birthday is not the anniversary: Everyone gains a year on January 1st, not on their individual birthday. So a baby born on December 31st becomes two years old in Korean counting the very next day — even though they are just 24 hours old in international terms.

The gap between Korean age and international age is therefore: if you have had your birthday this year, your Korean age is your international age plus 1. If you have not yet had your birthday this year, your Korean age is your international age plus 2.

Korean Counting Age International Age

A Second System: 연나이 (Year Age)

Separate from the counting age, Korea also used a 연나이 (year age) system for specific administrative purposes. Under 연나이, everyone born in the same calendar year is considered the same age — your birth month and day are irrelevant. A person born in January and a person born in December of the same year are both "23 years old" in 2024 if they were born in 2001, under the 연나이 system.

연나이 was used for military conscription scheduling, certain welfare eligibility determinations, and student grade placement. It created situations where a December-born student was placed in the same school year as someone born nearly a year earlier.

What the June 2023 Reform Changed

The Civil Act (민법) amendment that took effect on June 28, 2023, standardized the official legal age in Korea to the international system (만 나이). This means:

• All official documents, contracts, medical records, and legal instruments now use international age as the default.
• Government benefit eligibility, insurance age brackets, and administrative cutoffs are calculated using international age unless a specific law explicitly states otherwise.
• "공식 나이" (official age) in government contexts now always means international age.

The reform was broadly popular. Polling before passage showed that roughly 70% of Koreans supported the change, primarily because the multiple age systems created frequent confusion and practical errors in administrative contexts.

What Did Not Change

Cultural age usage in everyday conversation — the 한국식 나이 or counting age — continues in social contexts. Koreans still ask "몇 살이에요?" in social settings and typically answer with their Korean counting age. School year cohorts (동갑) continue to bond around birth year rather than exact birthday. Military conscription scheduling still uses 연나이 as its reference point for when men must undergo their physical examination.

The reform changed the legal default, not the cultural habit. Understanding this distinction is important: a newly arrived expatriate who learns that "Korean age was abolished" and then gives their international age in a social context may still encounter confusion, as the counting age persists in daily conversation.

Practical Implications

For medical appointments: Korean hospitals now record age using international age in official records. When a doctor asks your age, the expected answer in a clinical setting is your international age.

For insurance policies: Insurance products that were priced on Korean age must be re-priced or re-calculated using international age. Many Korean insurers sent notifications to policyholders after the reform explaining the recalculation.

For employment age discrimination laws: The age discrimination framework uses international age thresholds following the reform.

For Koreans abroad: Korean expatriates dealing with Korean government agencies or banking institutions will find that official correspondence now uses international age by default, which eliminates the confusion that previously arose when, for example, a passport (which always showed international age) differed from a Korean ID document in its age context.

Use our Age calculator to see both your international age and your Korean counting age simultaneously, which can be useful when navigating contexts that still mix the two systems.