The Maya had very complex and interlocking calendar systems, which were as precise as modern day calendars. The Maya recorded time mainly using 3 interconnected calendars: the Tzolk'in (260 day count), the Haab (365 day count), and the Long Count. Most Maya dates were expressed as a combination
of the Tzolk'in and Haab. This combination is called a Calendar Round. 
Tzolk'in

The Tzolk'in consists of the numbers 1  13 alternating against a cycle of 20 day names, with their numberday combination restarting every 260 days (13 x 20 = 260). For example (see figure 1), the iteration starts with the day 1 Imix and proceeds for 13 days to 13 B'en, then continues another 7 days counted from 1 Ix (day 14), 2 Men (day 15), 3 Kib'(day 16), etc, to 7 Ajaw — for a total of 20 days. Then the days will start over again with Imix, but continuing with the number sequence 8, or 8 Imix.

Tzolk'in (20 day names) 
Imix  Chuwen 
Ik'  Eb' 
Ak'bal  Ben 
K'an  Ix 
Chikchan  Men 
Kimi'  Kib' 
Manik'  Kab'an 
Lamat  Etz'nab' 
Muluk  Kawak 
Ok  Ajaw 
Figure 1 
1 Imix  11 Chuwen 
2 Ik'  12 Eb' 
3 Ak'bal  13 Ben 
4 K'an  1 Ix 
5 Chikchan  2 Men 
6 Kimi'  3 Kib' 
7 Manik'  4 Kab'an 
8 Lamat  5 Etz'nab' 
9 Muluk  6 Kawak 
10 Ok  7 Ajaw 

Haab

The Haab cycle repeats a series of 18 months of 20 days each (019), with an additional month of 5 days at the end (18 x 20 + 5 = 365). The months cycle is very similar to ours, for example (see figure 2) the month Pop begins and counts through 20 days, then goes on to the next month Wo.

Haab (19 month names) 
Pop  Yax 
Wo  Sak 
Sip  Kej 
Sotz'  Mak 
Sek  K'ank'in 
Xul  Muwan 
Yaxk'in  Pax 
Mol  K'ayab' 
Ch'en  K'umk'u 
 Wayeb' 
Figure 2 
0 Pop (seating of Pop)  11 Pop 
1 Pop  12 Pop 
2 Pop  13 Pop 
3 Pop  14 Pop 
4 Pop  15 Pop 
5 Pop  16 Pop 
6 Pop  17 Pop 
7 Pop  18 Pop 
8 Pop  19 Pop 
9 Pop  0 Wo (seating of Wo) 
10 Pop  1 Wo 

Long Count 
To keep track of linear time, the Maya created a positional notation system known as the Long Count. This is a number, used similarly to our numerical "year 2008," counting "years" and days since the last Creation in 3114 BC. (The "years" here counted, called Haabs, are only 360 days long.) Each 'digit' of the Long Count is twenty times the next one,
just as each digit of 2 0 0 8 is ten times the value of the following. We call our system, based on 10's, decimal notation; while the Maya system is vigesimal, based on 20's. The Long Count system counts in increments of twenty which provide the quantity of the b'aktun (400 years), k'atun (20 years), tun (360 days), winal (months), and k'in (days).

For example, the Gregorian date records:
Monday, December 29th 2008 
Monday = One day in a named cycle of 7 days (week) 
29th = One in a numbered cycle of 28, 29, 30 or 31 days 
December = One in a cycle of 12 named months 
363 = One in a cycle of 365 days 
2.0.0.8 AD/CE = A count of years since the birth of a Christian cycle 

To compare, this same date as written by the Maya records:
7 Manik' 10 K'ank'in 12.19.15.17.7 
Manik' = One day in a named cycle of 20 days (tzolk'in) 
7 = One in a numbered cycle of 13 days 
K'ank'in = One in a cycle of 18 named months (haab) 
10 = One in a numbered cycle of 20 days 
12.19.15.17.7 = A count of years since the birth of a Maya Cycle 



Click on the various links below to learn more about calendrics, how to convert a Gregorian date into a Maya date, and the glyphs associated with Maya dates. 
Inga Calvin's Glyph Guide Section 1  Calendrics 
Date Conversions 
Mark Van Stone's It's Not the End of the World: What the Ancient Maya Tell Us About 2012 
David Bolles explains The Mayan Calendar, The Solar  Agricultural Year, and Correlation Questions 
Print Current Month Calendar 
