Should I enter a lunar or solar birth date?
Learn how to enter a recorded lunar birth date without confusing it with the Solar Terms used to calculate Saju pillars.
Short answer: Enter the calendar type written in the birth record. If the record gives a Gregorian date, choose solar. If it gives a traditional lunar date, choose lunar and identify whether it was a leap month.
Do not type lunar month and day numbers into a field that expects a Gregorian date. The same digits refer to different days.
Saju is not simply a lunar calendar
Even when a birth date was recorded in the lunar calendar, the Year and Month Pillars are calculated with Solar Term boundaries. The date is first converted to a real moment, then the Saju calendar rules are applied.
That is why “solar or lunar?” describes the input record, while “Solar Terms” describes part of the pillar calculation. They are not competing styles of Saju.
Leap months matter because the same lunar month number can occur twice. If the record does not say whether the month was intercalary, look for family documents or an official conversion source rather than guessing.
Near Ipchun or a monthly Solar Term, even a correct conversion needs the exact time zone and term moment. Save the original date notation alongside the converted result so the calculation can be audited later.
Related: Solar Terms and Seasons · Why do Saju apps disagree?