Convert dates between Gregorian and Mayan (Long count Calendar) calendars
The Mayan calendar is cyclic. Each cycle consists of 13 Baktuns (approximately 5,125 years).
The Mayan Long Count calendar consists of cycles: Baktun (144,000 days), Katun (7,200 days), Tun (360 days), Uinal (20 days), and Kin (1 day).