East Asian Age Systems: Korean, Chinese, and Japanese Age Calculation Methods

East Asian age calculation systems differ significantly from the international system. While most of the world counts age from 0 at birth and adds a year on each birthday, several East Asian traditions count age differently.

The Korean age system (used in South Korea for social contexts) counts 1 year at birth and adds a year on New Year's Day rather than birthdays. This means a baby born on December 31st becomes 2 years old on January 1st.

Traditional Chinese age (sui, 岁) also considers a child 1 year old at birth, with everyone turning a year older at the Lunar New Year rather than individual birthdays. The Vietnamese system follows a similar approach.

Japan officially uses the international system (manzai) but the traditional kazoedoshi system — which counts age the same way as Korean age — is still used in some rural traditions and religious ceremonies.

Our Age Calculator at Age Right Now supports multiple age systems including international, Korean, Chinese, and various calendar-based ages like Lunar, Hijri, Hebrew, and Hindu.