The Jewish Calendar

A traditional Biblical approach to reckoning time



The Jewish year starts on Rosh Hashanah, “the Head of the Year,” the day when Adam and Eve were created. The number of any given year is the amount of years which have elapsed since creation. To find the corresponding Jewish year for any year on the Gregorian calendar, add 3760 to the Gregorian number, if it is before Rosh Hashanah. After Rosh Hashanah, add 3761.


The Jewish calendar is based on lunar cycles. Towards the beginning of the moon’s cycle, it appears as a thin crescent. That is the signal for a new Jewish month. The moon grows until it is full in the middle of the month, and then it begins to wane until it cannot be seen. It remains invisible for approximately two days and then the thin crescent reappears and the cycle begins again.

The entire cycle takes approximately 29½ days. Since a month needs to consist of complete days, a month is sometimes twenty-nine days long, and sometimes thirty. Knowing exactly when the month begins has always been important in Jewish practice, because the Torah schedules the Jewish festivals according to the days of the month.

The first day of the month, as well as the thirtieth day of a long month, is called Rosh Chodesh, the “Head of the Month,” and has semi-festive status.

Dates of Holidays

The story is told that one man in a synagogue was overheard to ask another, “When is Hanukkah this year?” The other man smiled slyly and replied, “Same as always: the 25th of Kislev.” This humorous comment makes an important point: the date of Jewish holidays does not change from year to year. Holidays are celebrated on the same day of the Jewish calendar every year, but the Jewish year is not the same length as a solar year on the civil calendar used by most of the western world, so the date shifts on the civil calendar. Click here for a list of the exact calendar dates of major and minor Jewish holidays projected into the future.

The Jewish calendar has the following months:

Hebrew English Holiday Dates Length Civil Equivalent
Nissan (in Hebrew) 1. Nissan The New Year for Jewish kings and festivals is celebrated on Nissan 1; Passover starts on Nissan 15 30 days March-April
Iyar (in Hebrew) 2. Iyar Lag B’Omer on Iyar 19 marks the 33rd day of the Counting of the Omer 29 days April-May
Sivan (in Hebrew) 3. Sivan Shavuot commemorates the giving of the Law 50 days (“Pentecost”) after Passover on Sivan 6-7 30 days May-June
Tammuz (in Hebrew) 4. Tammuz 29 days June-July
Av (in Hebrew) 5. Av Tisha B’Av (the 9th of Av) commemorates historical Jewish tragedies 30 days July-August
Elul (in Hebrew) 6. Elul The New Year for animal tithes is celebrated on Elul 1 29 days August-September
Tishri (in Hebrew) 7. Tishri The High Holidays (Rosh Hashanah and Yom Kippur), Sukkot, Shmini Atzeret, and Simchat Torah 30 days September-October
Cheshvan (in Hebrew) 8. Cheshvan 29 or 30 days October-November
Kislev (in Hebrew) 9. Kislev Hanukkah celebrations start on Kislev 25 30 or 29 days November-December
Tevet (in Hebrew) 10. Tevet Conclusion of Hanukkah 29 days December-January
Shevat (in Hebrew) 11. Shevat Tu b’Shevat “New Year of the Trees” or Jewish Arbor Day 30 days January-February
Adar (in Hebrew) 12. Adar Purim 30 days February-March
Adar I (in Hebrew)
Adar II (in Hebrew)
12. Adar I (leap years only)
13. Adar Beit (in leap years)
Purim celebrated in Adar Beit
29 days February-March



According to the account in Genesis, when God created time He first created night and then day (And it was evening and it was morning, one day” – Genesis 1:5). Therefore, a Jewish calendar date begins with the night beforehand. While a day in the secular calendar begins and ends at midnight, a Jewish day goes from nightfall to nightfall. Shabbat begins on Friday night, and on those dates where certain activities are restricted – such as working on Shabbat or major holidays – the restrictions go into effect the night beforehand, except for most fast days which begin at dawn.