Hebrew Date Converter — Gregorian to Jewish Calendar & Back
Convert any Gregorian date to the Hebrew Jewish calendar — and any Hebrew date back to Gregorian. The result shows the Hebrew day, month name, year number in AM (Anno Mundi) and whether the year is a regular or leap year. Furthermore, a nearby holidays panel automatically identifies any major Jewish holidays falling within two weeks of the converted date.
How to use the Hebrew Date Converter
The Hebrew calendar structure
The Hebrew calendar is a lunisolar calendar — it follows the moon for months but adds an extra month periodically to stay aligned with the solar year. Furthermore, the calendar has 12 months in regular years and 13 months in leap years. Regular years have 353, 354 or 355 days; leap years have 383, 384 or 385 days.
| Month | Hebrew name | Season | Days |
|---|---|---|---|
| 7 (year start) | Tishrei תִשְׁרֵי | Autumn | 30 |
| 8 | Cheshvan חֶשְׁוָן | Autumn | 29 or 30 |
| 9 | Kislev כִּסְלֵו | Winter | 29 or 30 |
| 1 | Nisan נִיסָן | Spring | 30 |
| 9 (Ramadan equiv.) | Elul אֱלוּל | Summer | 29 |
Why the Hebrew year starts in the seventh month
The religious year begins on 1 Nisan (the first month). However, the civil and calendar year begins on 1 Tishrei — the seventh month — which is when Rosh Hashana (Jewish New Year) is celebrated. Furthermore, this apparent contradiction has deep roots in Jewish tradition. Moreover, the Hebrew year number changes on 1 Tishrei, making it the practical start of the new year for counting purposes.
How the Hebrew date conversion works
The algorithm uses absolute day counting — converting both the Gregorian and Hebrew dates to a continuous day count (Rata Die) measured from a fixed epoch, then finding the corresponding date in the target calendar. Furthermore, the Hebrew calendar uses the Molad — the mean new moon — as its calculation basis, and the year structure depends on precise arithmetic to stay within a few hours of the astronomical new moon.
Leap years in cycle = years 3, 6, 8, 11, 14, 17, 19 of the cycle
Elapsed days = molad-based calculation from year 1 AM
Year 1 AM = 6 October 3761 BCE in the proleptic Gregorian calendar
Why Hebrew years have variable lengths
The Hebrew calendar uses three possible year lengths — deficient, regular and complete — to ensure that certain holidays never fall on specific days of the week. Furthermore, Rosh Hashana may never fall on a Sunday, Wednesday or Friday. Similarly, Yom Kippur may not fall on a Friday or Sunday. These constraints — called Dechiyot (postponements) — cause the calendar to vary the lengths of Cheshvan and Kislev between 29 and 30 days to satisfy all conditions simultaneously.
Worked example: converting Rosh Hashana 5786
Rosh Hashana — the Jewish New Year — always falls on 1 Tishrei. For Hebrew year 5786 AM, when does it occur in the Gregorian calendar?
| Input (Hebrew) | Value |
|---|---|
| Day | 1 |
| Month | Tishrei (month 7) |
| Year | 5786 AM |
| Output (Gregorian) | Value |
|---|---|
| Long form | 22 September 2025 |
| Day of week | Monday |
| Year type | Regular year (12 months) |
What is the Hebrew calendar?
The Hebrew calendar is the official calendar of the Jewish people and the State of Israel. Furthermore, it governs all religious observances and many national holidays. Furthermore, it is lunisolar — months follow the moon, and a 13th month is added in leap years to stay aligned with the solar year. The year count uses AM — Anno Mundi — counted from the traditional creation date in Jewish theology.
Hebrew year 5785 AM corresponds roughly to September 2024 to September 2025 in the Gregorian calendar. Furthermore, the Hebrew year begins on 1 Tishrei in September or October with Rosh Hashana. The calendar has been in continuous use for over two millennia and remains the reference standard for Jewish religious dating.
Major Jewish holidays and their Hebrew calendar dates
Hebrew calendar dates define all major Jewish observances. Rosh Hashana occurs on 1 Tishrei. Yom Kippur occurs on 10 Tishrei. Sukkot begins on 15 Tishrei. Passover (Pesach) starts on 15 Nisan. Shavuot is on 6 Sivan. Moreover, Hanukkah begins on 25 Kislev and Purim falls on 14 Adar (or 14 Adar II in leap years). These dates correspond to different Gregorian dates each year because the Hebrew calendar shifts relative to the Gregorian calendar.
The 19-year Metonic cycle
The Hebrew calendar operates on a 19-year Metonic cycle with 7 leap years. Furthermore, this keeps it closely aligned with the solar year over time. Furthermore, this cycle ensures the Hebrew calendar stays closely aligned with the solar year over time. The leap years within the 19-year cycle are years 3, 6, 8, 11, 14, 17 and 19. Moreover, this is why Jewish holidays cycle through approximately the same Gregorian calendar dates every 19 years, drifting only a few days within that range.
Why Hebrew date conversion matters
Jewish communities worldwide observe holidays and lifecycle events on Hebrew calendar dates. Furthermore, Hebrew dating rules define all these observances. Bar and Bat Mitzvah dates come from Hebrew birthday equivalents. Yahrzeits are observed on the Hebrew anniversary of the death date. Furthermore, accurate Gregorian-to-Hebrew conversion is essential for all these observances.
Israeli legal documents carry Hebrew dates alongside Gregorian dates. Furthermore, Jewish schools and synagogues schedule events by the Hebrew calendar. Moreover, hospitals and employers use Hebrew converters to avoid scheduling conflicts with major Jewish holidays.
How the nearby holiday indicator helps scheduling
The nearby holiday indicator shows major Jewish holidays within 14 days of the converted date. Furthermore, this helps planners avoid scheduling conflicts. Moreover, a date one week before Yom Kippur often warrants rescheduling for events with Jewish participants.
Frequently asked questions
Related Date & Time tools
Every tool on LazyTools runs in your browser. Nothing is uploaded or stored.
Gregorian to Hijri Converter
Convert any Gregorian date to Islamic Hijri. Furthermore, full Arabic month names and Islamic significance are shown.
→Religious Calendar Hub
Compare Islamic, Hebrew, Hindu and Christian calendar dates. Additionally, view key observances across traditions by month.
→Moon Phase Calculator
Find the moon phase for any date. Furthermore, the Birth Moon Finder shows the natal moon with cultural meanings.
→Days Until Calculator
Count days until any event with 20 pre-loaded holidays. Additionally, a multi-event dashboard tracks ten countdowns at once.
→Calendar Generator
Generate a monthly calendar with named event markers. Furthermore, add Jewish holidays directly into the calendar grid.
→Date Difference Calculator
Exact gap between two dates in every unit. Additionally, milestone markers show every 100th and 1000th day.
→