How the Mayan Calendar Works

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The Long Count Calendar

A Mayan calendar column was found in Quirigua, Yucatan peninsula, Mexico, on August 13, 1929.
A Mayan calendar column was found in Quirigua, Yucatan peninsula, Mexico, on August 13, 1929.
Topical Press Agency/Getty Images

The Mayans designed the Long Count calendar to last approximately 5,125.36 years, a time period they referred to as the Great Cycle [source: Jenkins]. The Long Count calendar is divided into five distinct units:

  • one day - kin
  • 20 days - uinal
  • 360 days - tun
  • 7,200 days - katun
  • 144,000 days - baktun

To find the Lon­g Count date that corresponds with any Gregorian date, you'll need to count the days from the beginning of the last Great Cycle. But determining when the last cycle began and matching that up to a Gregorian date is quite a feat.

English anthropologist Sir Eric Thompson looked to the Spanish Inquisition to calculate the Mayan-to-Gregorian date conversion, known as the Thompson Correlation. Events that occurred during the Inquisition were recorded on both the Mayan Long Count calendar and the Gregorian calendar. Scholars then gathered dates that matched on both calendars and compared them to the Dresden Codex, one of four Mayan documents that survived the Inquisition. This codex confirmed the date long thought by Thompson to be the beginning of the current Great Cycle -- Aug. 13, 3114 B.C. [source: Mayan Long Count].

The Mayan pyramid in Chichen Itza.
The Mayan pyramid in Chichen Itza.
© Photographer: Roberto Vannucci | Agency:

Now that we have the beginning date of the Great Cycle, let's put the Long Count into practice. We'll take a date that's familiar to many Americans: July 20, 1969, the day Apollo 11 landed on the moon. In the Long Count calendar, this date is written as You'll notice there are five number places in the date. Reading from left to right, the first place signifies the number of baktuns since the beginning of the Great Cycle. In this case, there have been 12 baktuns, or 1,728,000 days (144,000 x 12) since Aug. 13, 3114 B.C. The second place relates to the number of katuns that have taken place. Then, it continues on to the right with the number of tuns, uinals and kins.

In recent years, as the conclusion of the Long Count calendar approaches on Dec. 21, 2012, doomsday theorists have predicted the worst. That Gregorian date is denoted as on the Long Count, signaling the end of the current Great Cycle.

However, Mayan scholars and natives dismiss the apocalyptic theories, noting that end of the calendar would be regarded as a time of celebration, much like modern-day New Year festivities [source: Stevenson]. There are also no Mayan inscriptions or writings that predict the end of the world when the Great Cycle concludes [source: MacDonald].

The most notable event slated for that 2012 winter solstice will happen in the sky. For the first time in around 25,800 years, the sun will align with the center of the Milky Way galaxy [source: Stevenson]. Although the event sounds impressive, astronomers claim that it won't have any effect on the Earth. And with that, the next Great Cycle will quietly begin anew.