Lunar Age Calculator

Calculate your age in lunar years

This lunar age calculator converts the time between your birth date and a selected date into lunar years, lunar months, and days. It also shows your total number of lunar months, making it easy to answer “how many moons old am I?” using a consistent astronomical month length.

How the lunar age calculation works

Enter your birth date and the date on which you want to calculate your age. The calculator first finds the total elapsed days, then divides that time by the average synodic month of 29.530588853 days. Twelve synodic months make one lunar year in this calculation, equal to about 354.37 days.

What your lunar age result includes

• Your age in complete lunar years, lunar months, and remaining days
• The total number of completed moon cycles since your birth date
• Your solar calendar age for a direct comparison
• The difference between your lunar age and solar age

Lunar age vs. solar age

A solar year is about 365.24 days, while the 12-month lunar year used here is about 354.37 days. Because a lunar year is roughly 10.88 days shorter, your age in lunar years gradually becomes higher than your age in solar years. The comparison in the result shows how those two ways of measuring elapsed time differ.

What this lunar age calculator does not calculate

“Lunar age” can also refer to traditional East Asian age counting, a baby’s age from conception, or a date in a regional lunar calendar. This tool does not calculate those systems, convert a birthday to a lunar calendar date, or predict the moon phase on a date. It specifically measures elapsed age using average astronomical synodic months.

Why is the result an estimate?

The actual time from one new moon to the next varies slightly. This lunar month calculator uses the standard average synodic month, so it provides a consistent age conversion rather than counting observed new moons or local moon phases.