(This should not be relied upon for practical halacha.When a question arises a Rabbi should be consulted.) 1.The poskim stress the importance of using the Jewish calendar for calculating years (ex.
The Maharam Shick (Yoreh Deah 171), in turn, extends this prohibition to any action that would cause people to think about avodah zara, even without mentioning it by name.
Therefore, he argues, since the secular calendar year is counted from the birth of Yeshu, it is biblically prohibited to use the secular calendar year.
A similar stringent ruling is expressed by other poskim (see Sefer Get Pashut 1, Hillel Omer Yoreh Deah 62, Yayin Hatom Orach Chaim 8, Beer Moshe ). Harav Ovadia Yosef zt”l (Yabia Omer Yoreh Deah 3:9), however, proves that there exists a very strong possibility that the secular dates do not correspond at all to the birth of Yeshu Hanotzri.
He argues that if the dates have nothing to do with the birth of Yeshu Hanotzri, there would be no hallachic issue with the secular date. Some object to this leniency on the grounds that as long as people think the date relates to avodah zara, they will be reminded of the avodah zara, and one will then violate a Torah prohibition by bringing the avodah zara to people’s attention (Beer Moshe ibid.
This is also the view of Harav Nosson Gestetner zt”l printed in Tzitz Eliezer ). The Tzitz Eliezer addresses this objection and explains that if the date really has no relevance to the avodah zara, and people only mistakenly equate the two, there would be no prohibition in using the secular date.
One is not responsible for the thoughts of others and as long as he does not mention the avodah zara, or something related to the avodah zara, he has not transgressed any prohibition.In addition, most people are not reminded of Yeshu Hanotzri when told the date.Therefore using this calendar system may not be hallachically permitted.The Maharam Shick strongly objected to using secular dates on tombstones.He explains that the Torah says (Shemos ) that we may not mention the names of other gods.The Gemara (Sanhedrin 63b) understands this prohibition to include one who tells his friend to meet him near a particular avodah zara.