Lunar birthday calculator
Many Korean families still celebrate birthdays by the lunar calendar, especially a grandparent’s. Enter a birth date to find its lunar date and the day it falls on in each coming year.
Why a lunar birthday moves around
A lunar month runs from one new moon to the next, about 29.5 days, so twelve lunar months come to about 354 days, eleven short of a solar year. A lunar birthday therefore arrives about eleven days earlier each year, until a leap month is added and it jumps about nineteen days later. Nineteen solar years are almost exactly 235 lunar months, so the two calendars nearly line up again every nineteen years: around ages 19, 38, 57 and 76, the lunar and solar birthdays fall on or close to the same day.
Leap months
To keep the lunar year in step with the seasons, seven leap months are added in every nineteen years. A leap month repeats the number of the month before it, so a year can have two sixth months, and the second is the leap one: 윤달, yundal. If you were born in a leap month, most years have no such month, and Korean families then celebrate in the ordinary month with the same number. If you were born on the 30th and the month has only 29 days that year, the 29th stands in. The calculator follows both customs.
| Year | Leap month | Solar dates |
|---|---|---|
| 2020 | Leap 4th month (윤4월) | May 23 – Jun 20 |
| 2023 | Leap 2nd month (윤2월) | Mar 22 – Apr 19 |
| 2025 | Leap 6th month (윤6월) | Jul 25 – Aug 22 |
| 2028 | Leap 5th month (윤5월) | Jun 23 – Jul 21 |
| 2031 | Leap 3rd month (윤3월) | Apr 22 – May 20 |
| 2033 | Leap 11th month (윤11월) | Dec 22 – Jan 19, 2034 |
| 2036 | Leap 6th month (윤6월) | Jul 23 – Aug 21 |
| 2039 | Leap 5th month (윤5월) | Jun 22 – Jul 20 |
Korean and Chinese lunar calendars
The two calendars follow the same rules but count days in different time zones: the Korean lunar calendar uses Korea’s time (UTC+9), the Chinese one uses UTC+8. When a new moon falls in the hour before midnight in China, it is already past midnight in Korea, and the month starts a day later there. Lunar New Year 2027 is an example: February 6 in China, February 7 in Korea. This calculator uses the Korean calendar published by the Korea Astronomy and Space Science Institute, so an occasional date may differ by a day from a Chinese almanac.
Lunar birthdays and saju
A saju chart does not use lunar months. Its months change at solar terms and its year at Ipchun, around February 4, so a lunar birth date is converted to a solar date first. That is why the chart calculator asks for the solar date, and why two people with the same lunar birthday can have different month pillars. Why saju uses Ipchun
FAQ
What is a lunar birthday?
The day of the lunar calendar you were born on, such as the 15th day of the 8th month. Its solar date changes every year, which is why families look it up each year.
How do I find my lunar birthday?
Enter your solar birth date in the calculator above. It converts the date to the Korean lunar calendar and lists the solar date of your lunar birthday for the coming years. If you already know your lunar birth date, switch the first box to Lunar.
What if I was born in a leap month?
Most years have no leap month with the same number, so Korean families celebrate in the ordinary month instead. In the rare years that repeat your leap month, the calculator uses it.
Is the Korean lunar calendar the same as the Chinese one?
Almost always. Because Korea’s calendar is calculated for UTC+9 and China’s for UTC+8, a month occasionally starts a day apart, as Lunar New Year does in 2027.
Do Koreans still celebrate lunar birthdays?
Many do, especially older people, and families often keep a grandparent’s birthday on its lunar date. Holidays such as Seollal and Chuseok follow the lunar calendar too. Younger Koreans mostly use their solar birthday.
Korean age calculator · Lunar birthday calculator · Lunar age calculator · Chinese gender calendar · Chinese zodiac calculator · Lunar New Year dates · Chinese calendar · Day pillar calendar