Biblical Calendar
How We Calculate the Biblical Calendar
This page summarizes the calculation method documented by 119 Ministries. The method begins with the patterns described in Genesis 1 and uses the sun, moon, and stars as timekeeping signs for days, months, years, and YHWH's appointed times.
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Questions about the Biblical Calendar?
Calendar questions can get complicated. Ask the 119 Assistant about our calculation methodology, conjunctions, appointed times, or why our dates may differ from other calendar approaches.
The foundational pattern
The 119 Ministries method understands biblical time as beginning in darkness. A new day begins when the sun sets, and a new lunar month begins with the dark moon at conjunction.
The sun marks days, the moon marks months, and the annual pattern of the heavens helps establish the year. Jerusalem is used as the reference point for establishing biblical days and months.
Establishing the first biblical month
The first biblical month is anchored to the lunar conjunction nearest the spring equinox. This combines the lunar cycle used for months with the solar season used to keep the spring appointed times in their intended season.
- Determine the spring equinox in Jerusalem.
- Find the lunar conjunction closest to that equinox in Jerusalem Time.
- Identify the first biblical night that contains the astronomical conjunction moment. If the conjunction occurs during the daytime, the method assigns it to the coming night because the moon is treated as a night sign and the biblical day begins at night.
- That establishes the beginning point from which the first month and the appointed times are counted.
In the 2026 calculation source, the spring equinox is listed as March 20, 2026, and the nearest lunar conjunction as March 19, 2026, at 3:26 AM Jerusalem Time.
Calculating the spring mo’edim
- Determine the spring equinox in Jerusalem.
- Find the lunar conjunction closest to the spring equinox in Jerusalem.
- Use the first biblical night that contains the astronomical conjunction moment to establish the first biblical month.
- Count evening-to-evening days to the 14th day of the first month for Passover.
- Observe the Feast of Unleavened Bread from the 15th through the 21st day of the first month.
- Identify the weekly Sabbath during Unleavened Bread. The following day is Firstfruits.
- Count seven Sabbaths from that weekly Sabbath. The day after the seventh Sabbath is Shavuot.
Calculating the fall mo’edim
- Count forward from the first biblical month to the seventh lunar conjunction.
- The first night and day of the seventh month is Yom Teruah (Day of Trumpets).
- The 10th night and day of the seventh month is Yom Kippur (Day of Atonement).
- The 15th through the 21st days of the seventh month are Sukkot (Feast of Tabernacles).
- The 22nd day of the seventh month is the Last Great Day.
Traditional observance
Purim
Determine the 12th biblical month using the same lunar-conjunction method. Purim is placed on the 14th and 15th nights and days of that month.
Traditional observance
Hanukkah
Determine the ninth biblical month using the same method. The calendar source begins Hanukkah on the 24th night and day of the ninth month and counts eight nights and days.
Why the dates are evening to evening
The calculation document consistently treats biblical days as evening to evening. That is why the calendar may show an observance as beginning on the evening before the civil calendar date most people associate with the daytime portion of the observance.
See the calculated dates
Return to the Biblical Calendar to view the calculated calendar cycles from 2025 through 2030.
View the Biblical Calendar