The Hebrew calendar has months of 29 or 30 days that follow the Moon, and adds a 13th month (Adar I) in 7 years of every 19 so that Passover stays in spring. Since the 4th century its rules are fixed arithmetic: the mean new moon (molad) and four postponement rules set the day of Rosh Hashanah, which never falls on a Sunday, Wednesday or Friday.
Years are counted from the traditional date of creation (Anno Mundi). The year number changes at Rosh Hashanah in September or October; months are listed here from Tishri.
Evenings and sources
The Jewish day and every holiday begin at sunset the evening before the civil date shown. Dates come from your browser's calendar data (Unicode CLDR / ICU), which implements the standard arithmetic rules exactly. Holiday dates are those of Israel where they differ (Simchat Torah); outside Israel some festivals add a day.
Questions
Good to know
What is the Hebrew date today?
In Jerusalem it is 7 Heshvan 5787 (Sunday, 18 October 2026). After sunset the next Hebrew date begins.
When is the next Rosh Hashanah?
Rosh Hashanah 5788 is on Saturday, 2 October 2027, beginning at sunset the evening before.
Why do Jewish holidays move in the Gregorian calendar?
Hebrew months follow the Moon, and the leap month added 7 times in 19 years pulls the calendar back toward the solar year, so a holiday can fall up to about a month apart from one Gregorian year to the next.
Is this a leap year in the Hebrew calendar?
5787 AM has 13 months: it is a leap year, with Adar I and Adar II.