In traditional Chinese age counting, a newborn baby is one year old. And everyone gets a one-year increment of age on Chinese (Lunar) New Year. So a baby born a day before Chinese New Year could be two years old a couple of days after birth.
This is very essential as errors always occur on miscalculating the age of mothers.
Note that the western calendar date of a lunar new year is different year by year. Chinese start counting age from the time of pregnancy, unlike the western system where age is calculated from the time of birth.
Since the period of pregnancy can vary, the age of the child is considered to be one year at the time of birth.
In the traditional Chinese age counting system, your age increases by one year on Chinese New Year and not on the day of your birthday. The number of days per year is less in a Chinese calendar. Therefore, when compared to English Calendar, you’ll be older according to the Chinese year calendar.
