This article discusses the various calendars related to the Bible starting with the Jewish:

Jewish (Hebrew) Calendar

The Jewish calendar began on March 10, 1446 B.C. when God talked to Moses on Mount Sinai. It contains a cycle of 19 years. 11 of the years are normal years with twelve months. 7 of the years are leap years with thirteen months. The leap years are years 3, 6, 8, 11, 14, 17, and 19. So a normal year has 353, 354, or 355 days. A leap year has 383, 384, or 385 days. This gives an average of 365.2468 days per year. However, this becomes inaccurate past 3,840 years.

1. Nissan – 30 days, Passover, Pentecost
2. Iyyar – 29 days
3. Siwan – 30 days
4. Tammuz - 29 days
5. Av – 30 days
6. Elul – 29 days
7. Tishri – 30 days, Day of Atonement, Tabernacles
8. Marhewswan – 29 or 30 days
9. Kislew – 29 or 30 days
10. Tebeth – 29 days
11. Shevat – 30 days
12. Adar I – 30 days
13. Adar II – 29 days, only on leap years

Maya Calendar

The Maya calendar dates back to at least 500 B.C. This calendar uses two main years of 260 days known as the Tzolkin and 365 days known as the Haab. The Tzolkin is divided into smaller 13 day cycles, while the Haab is divided into 20 day cycles. Both of these counts are used together to make up a Calendar Round, which lasts 73 Tzolkin years and 52 Haab years. This is the least common multiple of the two.

There is also a long count, which measures in increments of 1, 20, 360, 7,200, 144,000, 2,880,000, and 57,600,000 days. The next 144,000 day count occurs on December 21, 2012, which leads many to believe this is when the second coming will take place. However, the Maya calendar is not mentioned in the Bible. The number 144,000 is used, but it is referring to the barley overcomers, not to a length of time.

Julian Calendar

The Julian calendar was introduced by Julius Caesar in 46 B.C., and came into use in 45 B.C. It contains a cycle of 4 years. 3 of the years are normal with 365 days. The 4th year adds an extra day making it 366 days. This gives an average of 365.25 days per year. However, this becomes inaccurate past 40 years.

Gregorian Calendar

The Gregorian Calendar was first introduced by Pope Gregory XIII, who signed a decree for it on February 24, 1582. This is the calendar we use today. It contains a cycle of 4 years. 3 of the years are normal with 365 days. The 4th year adds an extra day making it 366 days. However, every 100 years, the extra day is subtracted. For example, the year 2000 was not a leap year. This gives an average of 365.2425 days per year. This was a lot more accurate than the Julian calendar, but still becomes inaccurate past 3,840 years.

360 Day Calendar

The 360 day calendar has exactly 30 days per month, with 12 months in a normal year. There are many people that argue that the Bible uses a 360 day calendar, especially when it comes to prophecy, such as Daniel’s seventy weeks. Without any leap years this would obviously be very inaccurate because it would be short 5 days per year. However, with the following adjustments it becomes extremely accurate:

1. add a 30-day month at the end of every 6 years, this gives 365 days per year

2. add a 30-day month at the end of every 40 years, so there will be 7 extra interval months in 40 years, this is as accurate as the Julian calendar, giving 365.25 days per year

3. subtract the 30-day leap month at the end of every 3,840 years, this is more accurate than the Gregorian year (what we currently use), giving 365.2421875 days per year

4. add a 30-day month at the end of every 13,824,000 years, giving 365.2421896701389 days per year

5. subtract the 30-day leap month at the end of every 88,473,600,000 years, giving 365.2421896697998046875 days per year

6. add a 30-day-month at the end of every 153,600,000,000,000 (153.6 trillion) years, giving 365.2421896698 days per year, which is the perfect time it takes the Earth to make one full rotation around the Sun


God made one rotation of the Earth around the Sun to be a strange amount of 365.2421896698 days per year instead of something simple like 100.000 days per year. This has two main effects. One, it makes it very hard to design a calendar to account for this odd fraction of days. Two, it makes it hard to calculate any kind of prophecy that is in years. It would seem that God did this on purpose. Remember that He wants His elect overcomers to have thoroughly studied and prepared before the second coming. When we look at the calendars, both the Jewish and Gregorian are fairly accurate. Even if you wanted to measure from creation till now, which is about 6,000 years, they are only off about one and a half months. What I find ridiculous is when people argue that a year is only 360 days and don’t make any adjustments as I discussed above. Why would God make a prophetic year 360 days, but an actual year 365.2421896698 days? God is not inconsistent with His own creation nor His own laws. However, man is inconsistent, and this is why there is confusion.

Return from Calendars to Bible Numerology >

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