[Written By Rabbi Moishe Lebovits – KOF-K Kosher Supervision]
The Jewish calendar plays an important role throughout the year. However, we make ample use of the secular calendar as well. Whenever we write a check or schedule an appointment with a non-Jew, we use the secular date. The issue of using secular dates has been addressed over the last couple hundred years. Is writing the date akin to saying it? We will also focus on the format of the writing, such as January 28th 2014 or 1/28/2014. Included in our discussion is whether one is allowed to write the secular date on a tombstone.
Throughout our history, we have used various criteria to count the years. At first, we counted from the exodus from Mitzrayim. At other times, we counted based on the non-Jewish years in order to maintain a good relationship with the government, and other times we counted from the creation. The latter is the overwhelming practice that is practiced by Jews.
D’oraisa or Not
The Maharam Shick vehemently opposes mentioning the secular year and holds that it is included in the issue d’oraisa of mentioning a different god. However, it seems that this is a lone opinion, since if this was actually an issur then it would be mentioned in the Gemorah or Rishonim.
Following in the Ways of the Non-Jews
The Torah states, “Do not follow in the ways of the non-Jews” The Rambam writes that one should be different than the non-Jews in his actions, his philosophy, and in his understanding. There is a major dispute among the Rishonim and Achronim as to the parameters of this issur. A practice that the non-Jews perform for their avodah zarah is forbidden for a Jew, even if the Torah says that it is a Jewish custom. The Maharik writes that even those non-Jewish practices whose reasons and origins cannot be found are still forbidden to Jews, since it would appear that we are copying them. Furthermore, all immodest practices that the non-Jews are associated with are forbidden to a Jew. Most poskim agree with the guidelines of the Maharik.
Some poskim wish to maintain that mentioning the secular dates is an issur of “following in the ways of the non-Jews.” However, as mentioned above, if there is a reason why the non-Jews have a certain practice then there is no issur for Jews to follow them. Accordingly, since there is a reason why the non-Jews count the years the way they do, Jews would not be restricted from doing so.
Earlier Poskim Mention the Secular Date in Their Letters
Many poskim over the years wrote the secular date on their responsa, such as the Chavos Yair, Rama, and Chasam Sofer. Others are not convinced that this proves that writing the secular date is permitted.
Those Who Are Against Using Secular Dates
The Maharam Shik (and others) maintains that it is forbidden to use the secular dates (his case was referring to a tombstone) since one is not allowed to mention other gods. Included in this is any action that can cause people to think about their avodah zarah even without mentioning it by name. In addition, other gedolim refrained from writing the secular date, and maintained that one should refrain from such activity as well.
The Be’er Moshe wrote extensively against using the secular date and maintained that it is ossur to do so. He always wrote ’80 or 980 on a check instead of 1980, and the bank never refused to honor his check.
Those Who Are Not Against Using Secular Dates
Many poskim are lenient in this regard, since there is no mention in Shulchan Aruch or its commentaries that the prohibition extends to thinking about avodah zarah without saying the name of the avodah zarah. Additionally it is unclear whether the non-Jews count their years from yoshkas birth or not. Rather, this is a simple number that is accepted by everyone. The opinion of Harav Ovadia Yosef zt”l is that although one can be lenient, it is better to avoid it if possible. Others say that the entire concern of writing the secular date is if one writes the date and concludes, “Like the numbers of the notzrim.” However, if one just writes the secular date without that addition, there is no concern. Therefore, if one just uses the date because he is in business with non-Jews and has no intention to refer to avodah zarah, it is permitted.
The Opinion of Some Contemporary Gedolim
The opinion Harav Chaim Kanievesky Shlita is that one should refrain from using a secular date on a check. This is especially easy in Eretz Yisroel where the secular date is not required. However, in Chutz La’aretz one can be lenient. Harav Moshe Feinstein zt”l was lenient, but Harav Yaakov Kamenetsky zt”l was stringent. This is the opinion of the Satmer Rav zt”l as well. Harav D’biliski Shlita holds that when we do business with non-Jews such as buying a home, filling out a contract, or various bank issues which all use the secular calendar, one may write the secular date.
Writing vs. Saying
Those who forbid mentioning the name of the non-Jewish month would forbid writing it as well. However, even according to those who are stringent one would be permitted to make photocopies of checks or papers which contain the secular date, since it is hard to avoid such a situation.
Until now we were discussing the issue of writing or mentioning the secular year. Now we will focus our attention on writing or mentioning the secular month.
The Jews were given the mitzvah of counting the months as the very first mitzvah, the first month being Nissan. The Ramban gives a remarkable explanation. At first, the Jews did not use names for months; rather they counted the number of months from Nissan. The reason for this was in order for us to remember that Hashem took us out of Mitzrayim in Nissan. However, when we left Bavel, we started using the Babylonian names of the months to remember the time when Hashem took us out of Bavel.
Names of Months
As mentioned before, the Ramban says that the names of the months came from Bavel. Others say that they were given at Har Sinai. Many of the names of the months are found in Nevi’im and Kesuvim. Shevet and Kislev are mentioned in Zecharya. Teves, Nissan, Adar and Sivan are mentioned in Megillas Esther.
The months of November and December are mentioned in halacha in regard to saying v’sein tal umatar.
In reality, the secular months are mostly not names of avodah zarah of any sort. May, June, July, and August are names of kings. Other months are simply numbers. For example, December is ten in Latin, November is nine, October is eight, and September is seven. February means purification and April is the time of growth. January and March are name of gods.
Using Secular Months
Based on the above, there are those who maintain that Jews may not count using the secular months since we are supposed to count with Jewish months. Using secular months would be in violation of this mitzvah. Others say the entire mitzvah only applies when the mitzvah of kiddush hachodesh was performed, and not at any different time. Accordingly, there should be no issue with writing or using the secular month. When required for business purposes, one may write or mention the name of the secular month as the first month (i.e. on a check etc).
An additional heter to write the non-Jewish month is because the non-Jews use a solar calendar, while we use a lunar calendar. Therefore, when writing the secular month one is not counting the Jewish months with a different name, so there is no issue. The issue of counting Nissan as the first month only applies when we count according to the moon, not according to the sun.
Although we did mention heterim as to why some use the secular dates, one should still realize that we should be separate from the non-Jews and not use the secular date when it is not necessary (i.e. celebrating a birthday or anniversary, etc). 
 Refer to Meseches Rosh Hashanah 2b.
 Meseches Gittin 80a. See Tosfas Meseches Rosh Hashanah 2a “l’malachim,” Gittin 80a “mipnei,” Yevamos 91b “malchos.”
 Tosfas Meseches Gittin 80b “zu,” see Shulchan Aruch E.H. 127, Choshen Mishpat 43.
 Y.D. 171.
 Kovetz Bais Aron V’Yisroel 67:page 82.
 Parshas Kedoshim 2:23, see Rashi, Eben Ezra. Refer to Parshas Achrei Mos 18:3.
 Hilchos Avodah Zarah 11:1.
 Refer to Tosfas Avodah Zarah 12b “v’ey,” Rashi and Ramban Vayikra 19:9, Bach Y.D. 178, Bais Yosef 178, Pri Hasadeh 1:48, Minhag Yisroel Torah 6:pages 19-28 in depth.
 Refer to Tosfas Avodah Zarah 11a “v’ehi,” Ran Sanhedrin 52b, see Bach Y.D. 178, Shulchan Aruch Hamikutzar 144:5.
 Shoresh 88, Bais Yosef ibid.
 Refer to Darchei Moshe 1, Rama 178:1, Maharam Shick Y.D. 178.
 Chemdas Tzvi 4:33.
 Yabea Omer Y.D. 3:9.
 E.H. 1:43.
 Chemdas Tzvi 4:33, Beer Moshe 2:18.
 Y.D. 171.
 Yayin Hatov 8, Pri Hasadeh 1:3, Sharei Tzedek Y.D. 199, Yalkut Yosef 7:page 92. Refer to Yafei Leleiv Y.D. 178:3.
 Darchei Chaim V’sholom page 381:footnote 1.
 Oz Nedberu 12:38.
 2:18-19. Refer to Yisroel V’hazemanim 2:pages 935-941 in footnote in depth.
 Beer Moshe 2:18:page 39. Refer to V’ein Lamo Michshal 2:pages 98-100.
 Yabea Omer Y.D. 3:9. However, refer to Beer Moshe 2:18 who says this does not make a difference.
 Ibid. Refer to V’yalkut Yosef 13:9:pages 35-35b.
 Tzitz Eliezer 8:8.
 Yayin Hatov 8, Sharei Halacha U’minhag Y.D. pages 48-49, Yabea Omer Y.D. 3:9, Tzitz Eliezer 8:8.
 Refer to Orchos Rabbeinu 1:page 347.
 Meor Yeshoshua 36. Refer Kinyan Torah 1:55:4.
 Divrei Yoel O.C. 15:pages 89-90.
 Opinion quoted in Kovetz Bais Aron V’Yisroel 68:page 110.
 Refer to Maharam Shick Y.D. 171, Bais Yitzchok Y.D. 152.
 Opinion of Beer Moshe quoted in Oz Nedberu ibid.
 Regarding mentioning the days of the week that correspond to Shabbos see Shemos 20:8, Ramban, Mechilta Yisro ibid, Ritvah Meseches Rosh Hashanah 3b, Shulchan Aruch E.H. 126:3, Charedim 9:33, Chai Adom Shabbos 1:1, Kaf Hachaim 132:26, Aruch Hashulchan O.C. 242:1-2, Sharei Halacha U’minhag O.C. 88, Divrei Yoel O.C. 15 in depth, Kovetz Bais Aron V’Yisroel 71:pages 119-134 in great depth. Sunday in Yiddish is Suntig – which means Sun – day. Monday is Muntik– Mun is Moon and tug is day. Wednesday is Mitvach which means middle of the week (refer to Kovetz Bais Aron V’Yisroel 71:pages 133-134).
 The poskim question why this is not brought in the Sefer Hamitzvahs (Refer to Minchas Chincuh 311:5, Kovetz Bais Aron V’Yisroel 68:pages 101-104.
 Shemos 2:12.
 Rosh Hashanah 7b. Refer to Meiri, Ritvah.
 Shemos 2:12.
 Refer to Ritvah Meseches Rosh Hashanah 3a. See Binyan Shlomo O.C. 22 in depth.
 Bnei Yisoschor Nissan 1:6. Refer to Meseches Rosh Hashanah 7a.
 Refer to Meseches Rosh Hashanah 7a, Shulchan Aruch Y.D. 126, Gra. See Aruch Hashulchan E.H. 127:44.
 Zecharya 7:1.
 Zecharya 1:7. See Nechemya 1:1.
 Megillas Esther 2:16
 Ibid 3:7. See Nechemya 2:2.
 Megillas Esther 3:13.
 Ibid 8:9.
 Bais Yosef O.C. 117, Kitzur Shulchan Aruch 19:5,
 Refer to Kovetz Bais Aron V’Yisroel 68:pages 109-110.
 Lechem Hapanim on Kitzur Shulchan Aruch 62:1, Ginzei Yosef 106, Beer Moshe 2:18:5.
 Refer to Binyan Shlomo O.C. 22.
 Tzitz Eliezer 8:8. See Tzitz Eliezer 20:13:4.
 Ginzei Yosef 106, Avnei Yushpe 1:153:3. Refer to Yabea Omer Y.D. 3:9.
 Teshuvos V’hanhagos 1:830.
 Avnei Yushpe 1:153:3.