Hebrew Date Converter (Gregorian ↔ Jewish Calendar, with Holidays)

How it works

Year Y begins at the molad of Tishrei: months elapsed = ⌊(235Y − 234) ÷ 19⌋; molad = 29 d 12 h 793 parts per month (1 hour = 1,080 parts) · postponements (dechiyot): Rosh Hashanah never on Sunday, Wednesday or Friday, plus the GaTaRaD and BeTU'TaKPaT rules · leap years: years 3, 6, 8, 11, 14, 17 and 19 of each 19-year cycle add Adar I

The Hebrew calendar is lunisolar: months follow the Moon (29 or 30 days), and seven extra months every 19 years keep Passover in spring. Since the 4th century it has been fully arithmetic: each year starts from the computed mean new moon (molad) of Tishrei, adjusted by fixed postponement rules so that Yom Kippur never falls next to Shabbat. A year therefore has 353, 354 or 355 days, or 383–385 in a leap year. The converter applies these rules exactly, following Reingold & Dershowitz's Calendrical Calculations.

Worked example

Sunday, October 4, 2026 (before sunset) is 23 Tishrei 5787 — כ״ג תשרי תשפ״ז, Simchat Torah outside Israel. Year 5787 is a leap year of 13 months and 385 days; it began with Rosh Hashanah on Saturday, September 12, 2026, and Passover falls on Thursday, April 22, 2027.

Sources: Reingold & Dershowitz, Calendrical Calculations (Cambridge University Press) · Hebcal — Jewish calendar

Frequently asked questions