Read the result in the right order
A lunar result shows the lunar year, numbered month and day. If it says “leap month”, keep that label with the date. The Gregorian year and lunar year can differ in January and February, before Lunar New Year. This converter handles Gregorian dates from 1901 through 2099; dates at the beginning of 1901 can belong to lunar year 1900.
Why a leap month is not an extra day
A leap month repeats a month number within a lunar year. It is a whole additional month, not February 29. In 2023, ordinary month 2 began on February 20, while leap month 2 began on March 22. Entering lunar year 2023, month 2, day 1 therefore needs a leap-month choice to identify one date. Most years do not have a leap month; an impossible choice is rejected.
Planning a lunar birthday
First convert the original Gregorian birthday and record the lunar month, day and leap status. Then use Lunar → Gregorian with the year you want to check. If a leap-month birthday has no matching leap month in that year, the converter will not invent a replacement. Families use different celebration conventions; agree on one before choosing an ordinary month instead. A lunar month can have 29 or 30 days, so day 30 is not valid in every month.
Calendar scope and checking a date
These are Chinese civil-calendar date labels. The form does not convert a birth instant between time zones or determine an astronomical event at your location. Compare important dates with the Hong Kong Observatory calendar tables. Far-future dates near midnight can differ by a day between astronomical calculations; the Observatory documents this limitation, including new moons in 2057, 2089 and 2097.
Sources and calculation method
Hong Kong Observatory conversion tables · 2026 calendar reference · lunar-javascript calculation library
Calculated locally with lunar-javascript 1.7.7. NineHound’s examples and boundary tests are described in our methods; this does not imply independent validation of every date in the supported range.