What Long Count period equals 20 tuns, about 19.7 years?

In the Maya Long Count, 20 tuns equal one kʼatun, or kʼatun.

A tun contained 360 days: 18 periods called winals, each made up of 20 kʼins, or days. Twenty tuns therefore made 7,200 days, approximately 19.713 tropical years. The kʼatun occupied the second position from the left in the standard five-part Long Count notation.

The Maya used the Long Count to record dates across spans longer than the roughly 52-year Calendar Round. This made it especially valuable for monumental inscriptions, which could place a ruler, ceremony, or historical event in an unambiguous chronological framework.

Kʼatun endings mattered ceremonially. Maya communities marked them with rituals, and at Tikal, twin-pyramid complexes were associated with these occasions. The period also appeared in royal age and succession traditions. Twenty kʼatuns formed a bʼakʼtun, so a bʼakʼtun was much longer than a kʼatun. The 2012 date that attracted apocalyptic speculation was a bʼakʼtun transition, not the end of Maya time itself.