孔子生年、月、日問題是完全有條件研究清楚的。孔子生於夏曆八月二十一日或二十七日皆不可信。孔子當生於魯襄公二十一年，魯襄公二十二年而孔子生一方面係由實歲與虛歲轉換所致誤，另一方面係由周正與夏正轉換所致誤。一言以蔽之，孔子當生於魯襄公二十一年夏曆十二月二十三日。孔子之誕辰為魯襄公二十一年夏曆十二月二十三日完全不必轉換為西曆。

There are many conditions enough to make clear or ascertain the birthday of Confucius which is lunar calendar 23rd December which was mistaken as lunar calendar 21st or 27th August of Duke Lu Xiang 21 year(B.C.552) which was mistaken as Duke Lu Xiang 22 year(B.C.551) on the one hand because of the mistake of real Age translated to nominal Age, on the other hand because of the mistake of Zhou calendar translated to lunar calendar.