15.5.78.10 Mayan Long Count

The Mayan Long Count is a calendar consisting of 5 cycles that indicate the number of days since the last beginning of the full cycle. The name, definition, and length of each cycle is indicated in the following table.

  Name       Definition            Length
   k'in      = 1 day                1 day
 winal       = 20 k'in             20 days
   tun       = 18 winal           360 days
 k'atun      = 20 tun           7,200 days = about 20 years
b'ak'tun     = 20 k'atun      144,000 days = about 394 years
(full cycle) = 20 b'ak'tun  2,880,000 days = about 7885 years

a particular date in the Long Count is written as a set of five numbers, one for each subcycle, separated by periods (.). For example, the date 1.2.3.4.5 means 1 b’ak’tun, 2 k’atun, 3 tun, 4 winal, 5 k’in after the beginning of the full cycle. The beginning of the last cycle, at long count 0.0.0.0.0, is thought to correspond to 6 September -3113 C.E.

The Long Count 13.0.0.0.0 corresponds to 21 December 2012 C.E., and the current full cycle will be complete on 13 October 4772 C.E. The calendar function can return, in text form, the Long Count corresponding to any date.

For the Mayan Haab’ and Tzolk’in calendars, see Mayan Tikal Calendar.

Further reading: The Book of the Year: Middle American Calendrical Systems, by Munro. S. Edmonson; University of Utah Press, 1988.