假設身份證號在A2單元格
=IF(MONTH(NOW())<MONTH(DATE(MID(A2,7,4),MID(A2,11,2),MID(A2,13,2))),INT(YEAR(NOW())-YEAR(DATE(MID(A2,7,4),MID(A2,11,2),MID(A2,13,2))))-1,IF(MONTH(NOW())>MONTH(DATE(MID(A2,7,4),MID(A2,11,2),MID(A2,13,2))),YEAR(NOW())-YEAR(DATE(MID(A2,7,4),MID(A2,11,2),MID(A2,13,2))),IF(DAY(NOW())>=DAY(DATE(MID(A2,7,4),MID(A2,11,2),MID(A2,13,2))),YEAR(NOW())-YEAR(DATE(MID(A2,7,4),MID(A2,11,2),MID(A2,13,2))),YEAR(NOW())-YEAR(DATE(MID(A2,7,4),MID(A2,11,2),MID(A2,13,2)))-1)))
其實也可以根據任意時期計算, 例如, 只需將NOW()替換為"2018-08-08"