Katuns

Katuns are a unit of time in the Maya Long Count calendar. A Katun equals 20 tuns, or 7,200 days, which is about 19.7 solar years. The term comes from the Yucatec Maya word katun, meaning “twenty tuns.” In the Long Count, dates are written as five numbers: Baktun.Katun.Tun.Uinal.K'in. There are 20 Katuns in a Baktun, and there are 20 tuns in a Katun; the Tun position, however, is based on 18 uinal rather than 20, giving a Tun length of 360 days. The Uinal is 20 days, and a K'in is a single day.

The Katun is the second major unit in the Long Count, making it a key subdivision for recording centuries of Maya history. Numbers in the Katun place range from 0 to 19. In inscriptions, Katun counts appear alongside other units to indicate dates, reigns, and event timelines, providing a framework for calendrical and historical notation.

In modern scholarship, the Maya Long Count is correlated with the Gregorian calendar using a correlation constant. The most widely used is the GMT correlation, which places 0.0.0.0.0 at August 11, 3114 BCE (proleptic Gregorian). Under this system, 13.0.0.0.0 corresponds to December 21, 2012 CE. The rollover to a new Katun or Baktun is a calendrical cycle boundary, not a singular predictive event, and remains a focus of scholarly interpretation rather than apocalyptic speculation.