✡️ Hebrew Calendar Converter
See any Gregorian date in the Hebrew calendar, the lunisolar Jewish calendar whose leap years add a 13th month. Computed on your device.
Hebrew
20 Elul 5786
Wednesday · Jewish lunisolar calendar; leap years add a 13th month (Adar I/II).
Forward conversion uses your browser's built-in ICU calendar data; reverse inverts it exactly. All computed on your device.
How the hebrew calendar converter works
The Hebrew calendar is lunisolar: months follow the moon (29 or 30 days) but an extra month (Adar I) is inserted in 7 of every 19 years to keep the festivals aligned with the seasons, so a common year has 12 months and a leap year 13. This converter expresses any Gregorian date in the Hebrew calendar using your browser's ICU data. Years are counted AM (Anno Mundi) from the traditional date of creation, currently around 5786. The 19-year cycle (called the Metonic cycle) works because 19 solar years almost exactly equal 235 lunar months, 12 ordinary years of 12 months plus 7 leap years of 13, which is what keeps Passover in spring century after century. Year length itself varies between 353 and 385 days depending on whether it is a leap year and on two small calendrical adjustments.
Because of the leap-month system, the Hebrew calendar's months don't map to a fixed number the way a 12-month calendar does, which is why this page converts Gregorian dates into Hebrew ones rather than the reverse. Note too that the Hebrew day begins at sunset, so a date here corresponds to the daytime; the preceding evening already belongs to that Hebrew date.
Frequently asked questions
How does the Hebrew calendar handle leap years?
It adds a thirteenth month (Adar I) in 7 years out of every 19-year cycle. This keeps Passover in spring and the other festivals in their seasons, reconciling the lunar months with the solar year.
What does AM (Anno Mundi) mean?
"In the year of the world", the Hebrew year count from the traditional date of creation. The current Hebrew year is around 5786.
Why does this tool only convert Gregorian to Hebrew?
The leap-month system means a Hebrew month number alone is ambiguous, so a reliable reverse conversion needs the month by name. This page focuses on the common direction, Gregorian date in, Hebrew date out, done exactly via your browser's calendar data.
Does the Hebrew day start at midnight?
No, the Hebrew day begins at sunset the evening before. A Gregorian date shown here maps to the daytime portion; the evening beforehand is already the same Hebrew date.
Which month is added in a leap year?
A second month of Adar. The extra month, Adar I (also called Adar Aleph), is inserted before the usual Adar, which then becomes Adar II, so a leap year has 13 months. Purim and other Adar observances fall in Adar II in a leap year, keeping them roughly a month before Passover.
Why do the Hebrew and Gregorian years not line up?
The Hebrew year begins at Rosh Hashanah in the autumn (September or October), not on 1 January, so a single Hebrew year straddles two Gregorian ones. That is why a given Gregorian date can map to one of two Hebrew year numbers depending on whether it falls before or after Rosh Hashanah.
Is the conversion local?
Yes, the Hebrew calendar ships in your browser, so it runs on your device and works offline.