The Chinese lunar calendar differs from the standard Western, Gregorian calendar in many respects. According to Helmer Aslaksen, each calendar year is assigned a specific animal, the year does not begin on January 1 like the Gregorian calendar, and the Chinese calendar refers to all newborn babies as already one year old. Therefore, a person who is three years old according to the Gregorian calendar is considered four years old according to the lunar calendar. For all these reasons it can be difficult for non-Chinese to determine their birth dates and animals. Fortunately, the process is now straightforward thanks to modern technology.
Collect the relevent birth information. You will need to know the month, day, and year of the person whose lunar birth date you wish to calculate.
Go to China Caps' lunar birth date calculator at asia-home.com/china/cncaps.php?lang=en. This website hosts the most well known lunar birth date calculator. Insert the person's birth information under "1. Enter Gregorian Date of Your Birth."
Press "Enter" on your keyboard.
The fourth row from the top lists your "Chinese Date of Your Birthday." The result will list your cycle, your Chinese year, the Gregorian year, and the month and date of your lunar calendar birth.
Interpret your results. Aslaksen explains that the "cycle" refers to which of the nineteen year cycles your birthday falls under. Every twentieth year the lunar calendar enters a new cycle. Someone born in 1970 and someone born in 1990 will be born in different cycles. The "Chinese year" refers to which animal is assigned to your birth year. You might be a rabbit, an ox, a tiger, or another animal. The month and date of your birth is assigned according to how many days and months after the Chinese New Year you were born. As the Chinese New Year's date on the Gregorian calendar changes from year to year, two people born on March 20 in two separate years according to the Gregorian calendar will not have the same lunar calendar birth day and month.
The most popular part of the Chinese calendar is the yearly assignment of an animal to each year. If you wish to know which animal was assigned to your birth year, check the resources below.
The Chinese lunar calendar is a very complicated document. In the interests of accuracy, it is a good idea to rely on one of the many accurate calculators than to try to determine your lunar birth date by hand.