Learn how the lunisolar Hebrew calendar works, why leap years add a month, how nightfall affects the date and how to convert between Hebrew and Gregorian dates.
A Hebrew date cannot be converted correctly by applying a fixed offset to a Gregorian date. The two calendars structure months, years and even the start of the day differently.
The Bethemesh Hebrew date converter converts in both directions. Understanding three ideas - lunisolar structure, leap months and nightfall - makes the result much easier to interpret.
Hebrew calendar months follow a lunar cycle, while the year is kept aligned with the solar seasons. A twelve-month lunar year alone would drift earlier through the seasons, so the Hebrew calendar periodically adds a thirteenth month.
That adjustment keeps festivals connected to their intended seasonal position.
In a Hebrew leap year an extra month is inserted. You will then encounter Adar I and Adar II.
This matters in reverse conversion. A reference such as “10 Adar” needs the correct year and, in a leap year, the correct Adar. A converter has to model the actual month structure instead of treating month numbers as a simple list of twelve.
A Gregorian civil day changes at midnight. In the Jewish calendar, the new date begins in the evening. Chabad describes the Jewish day as running from nightfall to nightfall.
This has practical consequences for birthdays, memorial dates and holidays. An event on a Wednesday evening can already belong to the next Hebrew date even though the Gregorian date is still Wednesday.
The converter therefore offers an after sunset option. Situations close to twilight can involve more precise halachic definitions, so a sensitive religious case may still require guidance from the relevant authority.
For a standard conversion:
This is useful for personal calendars, archives, family dates and cross-checking records written in different calendar systems.
In the other direction, enter the Hebrew day, month and year. The converter finds the corresponding Gregorian date and handles leap-year Adar months.
The calendar conversion gives you the civil correspondence. It does not by itself decide every rule attached to a particular religious observance.
Date conversion answers which Hebrew date? Shabbat times answer when do the relevant Friday-evening and Saturday-evening solar boundaries occur at this location?
Those times depend on location and season. Use the Shabbat times calculator for candle-lighting, Friday sunset, Saturday sunset and a configurable Havdalah estimate.
The companion guide Shabbat times: sunset, candle-lighting and Havdalah explains why different calendars can show slightly different end times.
The Hebrew calendar combines lunar months with solar-season correction, inserts an extra month in leap years and changes dates in the evening rather than at midnight. Those are the main reasons manual conversion is easy to get wrong.
A converter handles the calendar mechanics; context still matters for twilight and observance-specific rules.
The extra month keeps lunar months aligned with the solar seasons.
The evening boundary is central, but the period between sunset and full nightfall has detailed halachic definitions. Consult the appropriate authority for a case where the exact boundary matters.
Yes within the range supported by the calendar engine, but historical research should also check which civil calendar was actually in use in the place and period being studied.
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