Hebrew Date Converter (Jewish Calendar)
Enter a date – the converter shows the Hebrew date with the month name, whether the Jewish year is a leap year and when Rosh Hashanah falls. In reverse, it finds the Gregorian day for any Hebrew date.
Source: ECMA-402 – Intl.DateTimeFormat (Kalender-Erweiterung -u-ca-). Updated: .
How it is calculated
How the Jewish calendar is structured
The Jewish (Hebrew) calendar is a lunisolar calendar: months follow the moon (29 or 30 days), and the year is kept in line with the solar year by adding leap months, so that Passover always falls in spring. Years (AM, “Anno Mundi”) are counted, according to tradition, from the creation of the world: the year 5787 begins on 12 September 2026.
How to convert a Hebrew date
- Choose the direction: Gregorian → Hebrew or the other way round.
- Enter the date – or the Hebrew year (AM), month and day.
- Read the Hebrew date, whether it is a leap year and the date of Rosh Hashanah.
Example: 28 September 2026 is 17 Tishrei 5787. The year 5787 began with Rosh Hashanah on 12 September 2026; 5788 begins on 2 October 2027.
The months
The civil year begins with Rosh Hashanah in autumn: Tishri, Heshvan, Kislev, Tevet, Shevat, Adar, Nisan, Iyar, Sivan, Tamuz, Av, Elul. The month names in the converter come directly from the Unicode calendar data (CLDR), spelled as usual in each language.
Leap year: Adar I and Adar II
In 7 out of 19 years (years 3, 6, 8, 11, 14, 17 and 19 of the cycle) a 13th month is added: Adar becomes Adar I and Adar II. Purim is then celebrated in Adar II. 5787 is such a leap year. A year therefore has 353 to 355 days (common year) or 383 to 385 days (leap year).
The day begins in the evening
A Jewish calendar day begins at sunset on the previous day. Rosh Hashanah 5787 falls on Saturday, 12 September 2026 – it is celebrated from the evening of 11 September 2026. The converter assigns each Gregorian day the date that applies during daytime and also names the previous evening.
How does the tool calculate?
The conversion uses the Hebrew calendar built into every browser under ECMA-402 from Unicode CLDR/ICU (hebrew). For the reverse direction, the converter searches for the day whose Hebrew date matches exactly. It covers the years 1900 to 2100 (5660–5861). More calendars: Islamic calendar, Chinese calendar.
More calendars: the Chinese calendar converter, the Hijri calendar converter and the Persian calendar converter.
Frequently asked questions
What Hebrew year is it?
Since Rosh Hashanah on 12 September 2026 it is the year 5787. The year 5788 begins on 2 October 2027 (eve on 1 October 2027).
When is a Jewish year a leap year?
In years 3, 6, 8, 11, 14, 17 and 19 of a 19-year cycle. Those years have Adar I and Adar II. 5787 is a leap year, 5786 is not.
Why do holidays begin the evening before?
Because the Jewish day begins at sunset. A holiday on 12 September therefore starts on the evening of 11 September and ends at nightfall on 12 September.
Which month do I choose for Adar in a common year?
Month 7 (“Adar II / Adar”). Adar I (month 6) only exists in leap years – the converter tells you if you select it.
How do I convert a birth date to the Hebrew calendar?
Choose Gregorian → Hebrew and enter the date. If the birth was after sunset, the Jewish day had already changed – enter the following date instead.
Sources and legal basis
- ECMA-402 – Intl.DateTimeFormat (Kalender-Erweiterung -u-ca-)
- Unicode CLDR, UTS #35 Part 4: Dates – Calendar Elements
- ICU User Guide – Calendar Classes
- Hebcal – Hebrew Date Converter
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