Age Calculator

Three ways Koreans count age

• International age (man-nai): You are 0 at birth and gain a year on each birthday. Since the 'Age Standardization Act' took effect in June 2023, this is the official standard for Korean law, contracts, and public administration.
• Korean age (se-neun nai): You are 1 at birth and everyone gains a year on January 1st. It is now officially abolished but still appears in casual conversation.
• Year age (yeon-nai): Current year minus birth year. Still used in specific laws such as military service and youth protection (e.g., legal drinking age).

How to calculate international age

If your birthday has passed this year: current year − birth year. If not: current year − birth year − 1.

One person, three ages

A baby born on December 31st becomes 2 years old in Korean age the next day, while still 0 in international age. This gap of up to two years is why 'How old are you?' can be a surprisingly complicated question in Korea.

Which age applies to drinking, smoking, and ID checks?

The legal age for alcohol and tobacco in Korea follows year age: anyone whose birth year makes them 19 or older that calendar year may purchase, regardless of birthday. Foreign visitors are checked by passport birth date on the same basis.