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Your lunar birthday, in Gregorian dates
Enter your lunar birthday to see its Gregorian dates and weekdays for the next 15 years at once. It also handles tricky cases like leap-month birthdays and birthdays on the 30th of a lunar month.
If you know your Gregorian birthday, head to the Age calculator or the Manseryeok calculator.
The next 15 years
The highlighted row is this year.
Once it's in Gregorian dates, you can look at your Saju too
Saju is read by the solar terms, not the lunar calendar. Enter the converted Gregorian date to get your Eight Characters.
Get the app for iPhone & AndroidWhy your lunar birthday moves every year
Twelve lunar months come to about 354 days, roughly 11 days shorter than a Gregorian year. So the same lunar date moves about ten days or so earlier on the Gregorian calendar each year.
Then, in a year with a leap month, it shifts back by about a month and returns to its usual place. In the table, you'll see the dates creep earlier and then jump back now and then. Those are the years with a leap month.
If your birthday is on the 30th of a lunar month
Lunar months are a mix of short months of 29 days and long months of 30 days. In years when that month is a short month, there is no 30th at all.
In that case, people usually celebrate on the 29th or on the last day of that month. This tool marks the years without that date and shows the last day of the month alongside.
If you were born in a leap month
The same leap month usually comes around only two or so times in 19 years. If you were born in leap month 5, you'd have to wait over a decade for the next leap month 5. That's why it's common to celebrate on the same date of the regular month.
This tool shows the leap-month date if that year has the same leap month, and the regular-month date if it doesn't, and labels which one it is.
Saju isn't read by the lunar calendar
Saju is based on the solar terms — the position of the sun, neither the lunar nor the Gregorian calendar. That's why, for a Saju reading, your lunar birthday is first converted to the Gregorian calendar and calculated from that Gregorian date and time. And the year changes not at Seollal (Korean Lunar New Year) but at Ipchun.
How it's calculated
This lunar data is built from new moons (sak 朔) in Korea Standard Time and the no-zhongqi leap-month rule. It was round-trip verified across 55,002 days from 1900 to 2050, and Seollal dates and leap-month lists were cross-checked against public sources. The conversion range is 1900–2050.
FAQ
Why does my lunar birthday fall on a different Gregorian date every year?
Because the lunar calendar follows the moon's waxing and waning, while the Gregorian calendar follows the Earth's orbit around the sun. Twelve lunar months come to about 354 days, roughly 11 days shorter than a Gregorian year, so the same lunar date moves about ten days or so earlier on the Gregorian calendar each year. Then, in a year with a leap month, it shifts back by about a month and returns to its usual place.
My birthday is on the 30th of a lunar month, but some years it doesn't exist
Lunar months are a mix of short months of 29 days and long months of 30 days, so in years when that month is a short month, the 30th simply doesn't exist. In those years, people usually celebrate on the 29th or on the last day of that month. This tool marks the years without that date and shows the last day of the month alongside.
If I was born in a leap month, when do I celebrate my birthday?
The same leap month usually comes around only two or so times in 19 years. So leap-month birthdays are generally celebrated on the same date of the regular month. This tool shows the leap-month date if that year has the same leap month, and the regular-month date if it doesn't, and labels which one it is.
Is Saju read using the lunar calendar?
No. Saju is based on the solar terms — the position of the sun, neither the lunar nor the Gregorian calendar. That's why, for a Saju reading, your lunar birthday is first converted to the Gregorian calendar and calculated from that Gregorian date and time.