Hebrew Calendar Converter
Convert a Gregorian date to the Hebrew (Jewish) calendar, or a Hebrew date back to the Gregorian one. You get the date in Latin and Hebrew script, the weekday, whether the year is a leap year, the length of every month and the dates of the main holidays — with a switch for events that happened after sunset, when the Hebrew day has already turned. Runs entirely in your browser — nothing is uploaded.
Pick a date to convert.
How to Use the Hebrew Calendar Converter
- 1. Choose the direction. Gregorian → Hebrew opens on today's date. For Hebrew → Gregorian, enter the day, pick the month and type the year (AM, anno mundi).
- 2. Mind the sunset. The Hebrew day starts in the evening, so a Gregorian date after dark is already the next Hebrew day. Tick the box if the moment you care about — a birth, a yahrzeit, a letter — was after sunset.
- 3. Read the result. You get the Hebrew date, the same date in Hebrew script, the Gregorian date, the weekday and the ISO date. For dates before October 1582 the Julian date appears too.
- 4. Check the year. Below the result are the year's length and type, a table of its months with the day each one begins, and the dates of Rosh Hashanah, Yom Kippur, Sukkot, Hanukkah, Purim, Passover and Shavuot.
How the Hebrew Calendar Works
The Hebrew calendar is lunisolar. Months follow the moon and are 29 or 30 days long, while a 19-year cycle with seven leap years keeps the festivals in their seasons: 12 months in a common year, 13 in a leap year. The extra month, Adar I, is added before Adar, which is then called Adar II. The leap years are years 3, 6, 8, 11, 14, 17 and 19 of the cycle — in practice, a year is a leap year when (7 × year + 1) mod 19 is less than 7. So 5784 was a leap year, while 5785 and 5786 are not, and 5787 is.
Years are counted from creation, with year 1 beginning on 1 Tishri, which fell on 7 October 3761 BCE in the Julian calendar. The year number changes at Rosh Hashanah, not on 1 January: from September or October a date is Gregorian year + 3761, and until then it is Gregorian year + 3760. Nisan is called the first month in the Bible, but the count of years turns over on 1 Tishri, the seventh.
| Month | Hebrew | Days |
|---|---|---|
| Tishri | תשרי | 30 |
| Marheshvan | חשוון | 29, or 30 in a complete year |
| Kislev | כסלו | 30, or 29 in a deficient year |
| Tevet | טבת | 29 |
| Shevat | שבט | 30 |
| Adar (Adar I in a leap year) | אדר (אדר א׳) | 29 (30 in a leap year) |
| Adar II, leap years only | אדר ב׳ | 29 |
| Nisan | ניסן | 30 |
| Iyyar | אייר | 29 |
| Sivan | סיוון | 30 |
| Tammuz | תמוז | 29 |
| Av | אב | 30 |
| Elul | אלול | 29 |
Marheshvan and Kislev are the two months whose length varies from year to year; Adar changes only in a leap year. Four postponement rules decide which weekday Rosh Hashanah falls on — chief among them that it is never a Sunday, Wednesday or Friday — and the length of the year adjusts to suit. A common year therefore has 353 (deficient), 354 (regular) or 355 (complete) days, and a leap year 383, 384 or 385. The mean Hebrew year is about 365.2468 days, a little longer than the Gregorian 365.2425, so the calendar drifts very slowly against the seasons.
The Hebrew Day Begins at Sunset
A Hebrew day runs from sunset to the next sunset, which is why holidays begin in the evening: Rosh Hashanah 5786 began at sunset on Monday 22 September 2025, and its first full day was Tuesday 23 September. A converter that takes only a Gregorian date cannot know the time or the place, so this one reports the Hebrew date in force during the daytime and lets you move to the next Hebrew day with the sunset box. At 8 pm on 22 September 2025 the Hebrew date is 1 Tishri 5786; at noon that day it is 29 Elul 5785. Sunset itself depends on your latitude and the season, so for a date near the line, check a local sunset table.
Worked Examples
- 1 January 2000 is 23 Tevet 5760, a Saturday. The year 5760 began on 11 September 1999.
- 23 September 2025 is 1 Tishri 5786, and 5786 is a regular common year of 354 days. It ends on 11 September 2026, the day before 5787 — a complete leap year of 385 days — begins on Saturday 12 September 2026.
- Passover (15 Nisan) in 5786 starts at sunset on 1 April 2026, so the first full day is Thursday 2 April 2026; Purim, on 14 Adar, falls on Tuesday 3 March 2026.
Accuracy and Limits
The converter implements the arithmetic calendar as set out in Reingold and Dershowitz, Calendrical Calculations: The Ultimate Edition (Cambridge University Press, 2018), and checks it against the rules of Maimonides and against the date library built into current browsers. Every day from Rosh Hashanah 5561 (September 1800) to Rosh Hashanah 5806 (September 2045) agrees with that library. Beyond that, the published rules and some date libraries part by a day in a few dozen far-future years, starting with 5807 (autumn 2046); this converter follows the published rules.
The calendar in this form was fixed in the fourth century CE (tradition says by Hillel II in 359), so earlier dates are the rules run backwards, and dates before 1582 are entered in the proleptic Gregorian calendar. Holiday dates are the first day as kept outside Israel; the dates of fasts that move to avoid Shabbat are not listed.
Hebrew dates in citations
Hebrew books and documents often give only a Hebrew year, which overlaps two Gregorian years: 5786 ran from 23 September 2025 to 11 September 2026. If a source also names the month, the table above narrows it to one year; otherwise cite what the source gives. For names and titles from Hebrew sources, How to Cite a Source in Another Language covers transliteration and translation.
Frequently Asked Questions
- What is today's date in the Hebrew calendar?
- The converter opens on today's date from your device's clock and shows the Hebrew date in force during the daytime. After sunset where you are, tick the sunset box to see the next Hebrew day, which has already begun.
- Why does the Hebrew date change at sunset?
- The Hebrew day follows the biblical pattern "there was evening and there was morning", so it starts at nightfall and ends at the next sunset. That is why Shabbat and every holiday begin on the evening before the date on a Gregorian calendar, and why a birth after dark is given the next Hebrew date.
- How many months does the Hebrew calendar have?
- Twelve in a common year and thirteen in a leap year. Leap years come seven times in each 19-year cycle and add a month of 30 days, Adar I, before the usual Adar, which then becomes Adar II. Purim is kept in Adar II in a leap year.
- Why does Rosh Hashanah fall on a different date each year?
- The calendar is lunisolar: twelve lunar months are about 11 days short of a solar year, and leap months make up the difference in a 19-year cycle. Rosh Hashanah therefore wanders between 5 September and 5 October in the Gregorian calendar, and it also never falls on a Sunday, Wednesday or Friday.
- How do I convert a Hebrew date to a Gregorian date?
- Choose Hebrew → Gregorian, enter the day, pick the month and type the year. The converter checks that the day exists — Marheshvan, Kislev and Adar change length from year to year — and returns the Gregorian date of the daytime, together with the evening on which that Hebrew day began.
- What does AM mean in a Hebrew year?
- AM stands for anno mundi, Latin for "in the year of the world". The Hebrew count starts from the traditional date of creation, so 5786 AM began in September 2025. Hebrew texts often drop the thousands and write 786 or the Hebrew letters for it.