What is the East Asian lunisolar calendar?
The lunisolar calendar tracks the moon's phases (new moon to full moon to new moon) while staying roughly aligned with the solar year. It's still used across Korea, China, and Vietnam to set major holidays β Lunar New Year (Seollal in Korea, Chinese New Year, TαΊΏt in Vietnam), the Mid-Autumn Festival, and traditional memorial days. This converter uses data from the Korea Astronomy and Space Science Institute (KASI) and covers dates from 1000 to 2050.
What is a leap month?
A lunisolar year is about 11 days shorter than a solar year, so every few years an extra month is inserted to keep the calendar in sync with the seasons β this is the leap month. A year with a "leap 5th month," for example, effectively has two 5th months. If a lunisolar birthday falls in a leap month, you must select that option correctly when converting.
What is the gapja (sexagenary cycle)?
Gapja combines the 10 "heavenly stems" with the 12 "earthly branches" to name years, months, and days in a repeating 60-term cycle β the same system behind the 12-animal zodiac. For example, a "Ding-You" year is a Year of the Rooster. This tool shows the gapja alongside every conversion, in Chinese characters as they're traditionally written.
Frequently Asked Questions
Can I just reuse last year's solar date for a lunisolar birthday?
No. The gap between the lunisolar and solar calendars shifts every year, so a lunisolar birthday lands on a different solar date each year β you need to reconvert it annually with a tool like this one.
What date range does this support?
Lunisolar dates from 1000-01-01 to 2050-11-18, and solar dates from 1000-02-13 to 2050-12-31. Dates outside this range can't be converted.
Why convert a memorial date to the solar calendar?
In Korea, traditional ancestral memorial rites (jesa) are often held on the lunisolar date of a person's passing. Since that date shifts on the Gregorian calendar every year, families use a converter like this to find the correct solar-calendar date to observe it on.