The Long Count calendar represents a cycle of time which is approximately 5,125 years. The span of the Long Count calendar is called the Great Cycle.
There are five digits in Mayan Long Count calendar, it starts at 0.0.0.0.0 and ends at 184.108.40.206.0 each zero from the right goes from 0-19 and the second digit from the right rolls over to 0 when it reaches 18.
The first day in the Long Count is written as 0.0.0.0.1
The 11th day in the Long Count is written as 0.0.0.0.11
The 19th day in the Long Count is written as 0.0.0.0.19, when each value was numerically accomplished to its maximum, the number would then reset to ‘0’ and the total will be carried forward into the next time cycle tto its left, therefore...
The 20th day in the Long Count is written as 0.0.0.1.0
0.0.0.1.5 means 25 days.
0.0.0.2.0 is equal to 40 days
0.0.1.0.0 does not represent 400 days, since the second digit from the right rolls over to 0 when it reaches 18, therefore it represents only 360 days.
This count continues until..
0.1.0.0.0 (about 20 years)
220.127.116.11.0 (about 400 years), this is also called one baktun.
Currently we are in the 12th baktun, and when we reach 13th baktun (18.104.22.168.0) it will falls on December 21, 2012 (in Gregorian calendar) which many people claim that day to be "the end of the world".
1 Kin = 1 day
1 uinal = 20 kin = 20 days.
1 tun = 18 uinal = 360 days (approx. 1 year).
1 katun = 20 tun = 7,200 days (approx. 20 years).
1 baktun = 20 katun = 144,000 days (approx. 394 years).