By Paul Dohrman Updated Mar 24, 2022

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A lunar year is based on a sequence of lunar phases. The average interval between successive new moons—the synodic month—is about 29.530 days. In many calendars, 12 lunar months compose a year. The Islamic calendar follows this pattern strictly, while the Chinese calendar also uses lunar months but anchors its New Year to a fixed Gregorian date each year.

Islamic Lunar Years

Step 1

Multiply your age in Earth years by 365 to get the total number of days lived.

Step 2

Add one extra day for each leap year (years divisible by four) that has occurred during your lifetime.

Step 3

Include the days that have passed since your most recent birthday and add them to the total from Step 2.

Step 4

Divide the sum by 29.53 to convert Earth days into lunar months.

Step 5

Discard any fractional part; the whole number is your age in Islamic lunar years.

Example: If the result of Step 4 is 43.23, you are 43 lunar years old.

Chinese Lunar Years

Step 1

Find the Gregorian dates of Chinese New Year for the year you were born and for the current year.

Step 2

If your birthday falls before that year’s Chinese New Year, subtract one from your birth year. For instance, born on Jan 16, 1976, with Chinese New Year on Jan 31, 1976, would use 1975 as the birth reference.

Step 3

If the current Chinese New Year has not yet occurred, subtract one from the current Gregorian year.

Step 4

Calculate the difference between the adjusted birth year and the adjusted current year, then add one. The addition accounts for the Chinese tradition of counting the time spent in the womb toward a person’s age.