The Hebrew calendar is a lunisolar calendar. Its current rules were pronounced in the 4th century C.E. by Patriarch Hillel II. New days start at sunset, new months start at a New Moon, and new years start in the northern hemisphere spring.
a Hebrew calendar year has 12 or 13 months, that each have 29 or 30
days. The month names and lengths in days are listed in the following
table. Biblical tradition lists Nisan as the first month but has the
new year start on the first day of Tishri. The
counts months from the start of the year in Tishri. The month numbers,
names, and lengths (in days) are listed in the following table
Number Month Name Length 1 Nisan 30 2 Iyyar 29 3 Sivan 30 4 Tammuz 29 5 Av 30 6 Elul 29 7 Tishri 30 8 Heshvan 29 or 30 9 Kislev 29 or 30 10 Tevet 29 11 Shevat 30 12 Adar â 30 (only present in leap years) 12/13 Adar (â ¡) 29
Leap days may be inserted at the ends of the months of Heshvan and Kislev, and a leap month Adar â may be inserted just before month Adar, which in that case is renamed to Adar â ¡. This means that any given year may contain six different numbers of days, as listed in the following table
Days Designation 353 deficient ordinary year 354 regular ordinary year 355 complete ordinary year 383 deficient leap year 384 regular leap year 385 complete leap year
There are 7 leap years in a fixed cycle of 19 years.
The epoch of the Hebrew calendar is sunset of 6 October -3760
C.E., which was taken to be the date of the creation of the world. The
Era of the Hebrew calendar is referred to as A.M. (= Anno Mundi). The
first noon after the epoch was the noon of 7 October -3760 C.E.,
calendar function equates 1 Tishri 1 A.M. with 7 October
For transforming from Hebrew calendar dates, years from -5879540 through 5878588 provide accurate results.