Hebrew date converter
Turn a Gregorian date into a Hebrew date, or the other way round.
How do I find the Hebrew date for a Gregorian date?
Pick a Gregorian date and the converter returns the Hebrew day, month and year. For example, October 28, 2026 is 17 Cheshvan 5787. Use the other tab to go from a Hebrew date to the Gregorian one. The Hebrew day begins at sundown, so for an event after sunset choose “after sundown” and the converter gives the next Hebrew date.
When is Rosh Hashanah in 2026?
Rosh Hashanah, 1 Tishrei 5787, falls on Sep 12, 2026 (Saturday); the holiday begins at sundown the evening before. The next Hebrew year, 5788, begins on Oct 2, 2027, 385 days later, because 5787 is a leap year.
Why does the Hebrew year have 12 or 13 months?
The calendar follows the Moon for months and the Sun for years. Twelve lunar months are about 11 days shorter than a solar year, so a 13th month is added in 7 of every 19 years (the Metonic cycle): years 3, 6, 8, 11, 14, 17 and 19 of the cycle. Year 5787 is year 11 of its cycle, so it is a leap year with an Adar I and an Adar II. The extra month keeps Passover in spring.
How long is a Hebrew year?
A common year has 353, 354 or 355 days and a leap year 383, 384 or 385 (all six lengths occur). The three lengths are called deficient, regular and complete. They differ only in two months: Cheshvan has 29 or 30 days and Kislev 29 or 30. Year 5787 has 385 days (complete leap year).
Why is Rosh Hashanah never on a Sunday, Wednesday or Friday?
The rule “lo ADU Rosh” forbids it. Most rabbinic authorities explain it so that Yom Kippur never falls on a Friday or Sunday, next to the Sabbath, and Hoshana Rabbah never falls on the Sabbath (Maimonides gives a different reason). In 5700–5899 the holiday fell on Monday 56, Tuesday 21, Thursday 67, Saturday 56 times; Sunday, Wednesday, Friday never.
Are the dates the same as my synagogue's calendar?
For the standard (rabbinic) calendar, yes: the month lengths and the year start follow fixed arithmetic rules, not observation of the Moon, and agree with Hebcal. The converter does not know your location, so it cannot give candle-lighting times, the exact start of a Sabbath or holiday, or the added second day of a holiday outside Israel. For religious observance, use a local authority or your congregation's calendar.
How the calendar is computed
The Hebrew calendar is arithmetic. A mean lunar month (the molad interval) is 29 days, 12 hours and 793 parts, where a part is 1/1080 of an hour. From a fixed starting molad, the molad of Tishrei of any year is found by counting the months elapsed: 235 months in each 19-year cycle. That molad is the starting estimate for Rosh Hashanah, and four postponement rules (dehiyyot) then decide the real day: if the molad is at or after noon, the day is moved one day later; the year may not begin on Sunday, Wednesday or Friday; a Tuesday molad of a common year at or after 9 hours 204 parts moves to Thursday (GaTaRaD); and a Monday molad after a leap year at or after 15 hours 589 parts moves to Tuesday (BeTU'TeKaPoT). The last two prevent a year of 356 or 382 days. The length of a year is the distance between two Rosh Hashanah dates, which sets whether Cheshvan and Kislev have 29 or 30 days.
Worked example: year 5787
Rosh Hashanah 5787 is Sep 12, 2026 and Rosh Hashanah 5788 is Oct 2, 2027: 385 days, so Cheshvan has 30 days and Kislev 30. The months in order are Tishrei (30), Cheshvan (30), Kislev (30), Tevet (29), Shevat (30), Adar I (30), Adar II (29), Nisan (30), Iyyar (29), Sivan (30), Tammuz (29), Av (30), Elul (29). Counting from Sep 12, 2026: October 28, 2026 is day 47 of the year, which lands on 17 Cheshvan. Passover (15 Nisan 5786) fell on Apr 2, 2026. The table under the converter lists these holidays for any year.
Limits of this converter
Months and years are exact, but many questions about Jewish dates are not purely calendar ones. Holidays outside Israel add a day for Passover, Shavuot and Sukkot. Fast days move when they fall on the Sabbath. Customs differ for a Hebrew birthday in a leap year, for a yahrzeit after the first year and for a bar or bat mitzvah date, and a congregation or rabbi decides which applies. Dates before the calendar was fixed in the fourth century CE are a projection, not the calendar people used then. The converter uses the Gregorian calendar in the proleptic form for every year, including before its adoption. For religious observance, use a local authority.
For calendar information only. For religious observance, such as the start of a holiday or a fast, use a local authority or your congregation's calendar. How we check our calculators.
Sources: Nachum Dershowitz and Edward M. Reingold, Calendrical Calculations (Cambridge University Press, 3rd ed., 2008), chapter on the Hebrew calendar (algorithm written independently; the book's text is not reproduced); results checked against the Hebcal converter and holiday list (hebcal.com) for 23 dates and for the holidays of 2024–2028 and 2031; postponement rules as summarized in the Wikipedia article “Hebrew calendar” (a secondary source). Related: Hijri date converter, Easter date calculator, date calculator, day of the week calculator and moon phase calculator.