Convert solar (Gregorian) dates to Korean lunar dates and vice versa. Covers 1901-2100, handles intercalation (leap) months, and displays the traditional Korean ganzhi year name. Runs entirely in your browser: no login, no installation.
The lunar calendar takes one month as a full cycle of moon phases, about 29.53 days. Twelve of those come to roughly 354 days, some eleven days short of a solar year, which is why the same lunar birthday lands about eleven days earlier on the solar calendar each year. Left alone that would drift Seollal into summer within a couple of decades, so roughly every two to three years an extra month is inserted to pull the calendar back in line. That inserted month is the intercalary, or leap, month.
If your family keeps birthdays or ancestral rites on the lunar calendar, this is why the solar date has to be looked up again every year. The rule rests on real astronomical calculation rather than simple division, so converting by hand is not practical.
In a year with an intercalary month, the sixth month, say, occurs twice: the ordinary sixth month and then the leap sixth month. For someone born on the fifteenth of the sixth lunar month, which one to observe in such a year varies by family. The ordinary month is the usual choice, and ancestral rites in particular are widely kept in the ordinary month rather than the leap one.
In this converter the leap-month option can only be switched on for months that actually have one. If you cannot select it, that year and month simply has no leap month and the ordinary date applies.
Each conversion also shows the date's ganzhi (the sixty-term sexagenary cycle) and its zodiac animal. The common confusion is when the animal changes. This tool uses the first day of the first lunar month as the boundary, so someone born in solar January still falls in the previous lunar year and takes the previous year's animal.
Some traditions in Chinese astrology instead place the boundary at Lichun, around 4 February, which means the animal for anyone born between January and early February can differ depending on the convention. For everyday use, the lunar new year boundary is the usual one.
Because the solar date shifts each year, a repeating calendar entry will drift out of sync. It is safer to look it up annually.
The solar-to-lunar direction is what you use to work out which lunar day a holiday or memorial falls on.
If the toggle stays disabled, that year and month has no leap month.
What it is, who it's for, how it works and why you'd use it.
A Lunar-Solar Converter converts dates between the Gregorian (solar) calendar and the Korean lunisolar calendar in both directions. It covers 1901 to 2100 and correctly handles intercalation (leap) months.
It is for office workers and small business owners who need to look up lunar-calendar anniversaries, memorial days and traditional holidays in the Gregorian calendar, or the reverse.
Select a conversion direction, enter a year, month and day, and the result is calculated instantly in your browser: including the traditional Korean ganzhi year name and zodiac animal.
It saves the annual calendar-flipping or search needed to cross-reference lunar and solar dates for any date from 1901 to 2100.