What is this?

This is an attempt to render the Mayan calendar in a more familiar “monthly” calendar format.

The idea of a monthly calendar is sort of alien to the Maya, who used two cycles to track the date and a modified base-20 numbering system to track the exact date:

• The Tzolkʼin cycle, which is a 260-day cycle based on combining 20 day names with 13 numbers, used for religious and ceremonial events and for divination;
• The Haabʼ cycle, which is a 365-day cycle consisting of 18 months of 20 day each, plus 5 days at the end of the year known as the Wayebʼ;
• The Long Count, represents the absolute number of days since the Mayan date of creation.

Since the Haabʼ is the closest equivalent to months in the Mayan system, this calendar application is based on the Haabʼ. This poses a problem, as in the Mayan system, the Long Count is used to track the absolute date and the cycles of Tzolkʼin and Haabʼ are unnumbered. To mitigate this issue, I numbered the Haabʼ cycles, with the date of creation in cycle 0.

How does Tzolkʼin work?

The Tzolkʼin is composed from two concurrent cycles—the number 1 to 13, and a list of 20 day names.

The day name are: Imix, Ikʼ, Akʼbʼal, Kʼan, Chikchan, Kimi, Manikʼ, Lamat, Muluk, Ok, Chuwen, Ebʼ, Bʼen, Ix, Men, Kibʼ, Kabʼan, Etzʼnabʼ, Kawak, and Ajaw.

Note that the day name and number cycles are completely independent and advance concurrently. This means that 1 Imix is followed by 2 Ikʼ and so on. There is no definite start or end to this cycle, but day names repeat every 260 days, which is the least common multiple of 13 and 20.

How does Haabʼ work?

The Haabʼ is a cycle of 18 months of 20 days each, counted from 0 to 19, plus 5 extra days at the end of the year called the Wayebʼ.

The 18 normal months are named Pop, Woʼ, Sip, Sotzʼ, Sek, Xul, Yaxkʼin, Mol, Chʼen, Yax, Sakʼ, Keh, Mak, Kʼankʼin, Muwan, Pax, Kʼayabʼ, and Kumkʼu.

The days of each month are counted from 0. So a year would start at 0 Pop, followed by 1 Pop, etc. The month of Pop ends at 19 Pop, which is followed by 0 Woʼ. The pattern continues until 19 Kumkʼu, after which we have 0 Wayebʼ. The last day of the year is 4 Wayebʼ.

Note that in the traditional Mayan system, the Haabʼ cycle repeats, but the iterations (“years”) are not numbered. Years were implemented in this version to allow the exact screen to be identified.

How do the Haabʼ years work?

In the traditional Mayan calendar, Haabʼ cycles are unnumbered. To help uniquely identify every screen, I introduced year numbers, with the date of Mayan creation as “year 0.”

In my system, the year number increases every time 0 Pop rolls around, with year 0 being defined as the year containing Mayan creation date (0.0.0.0.0 in the Long Count). This means that creation happens on 8 Kumkʼu in year 0, and the year continues until 4 Wayebʼ, after which the date is 0 Pop in year 1.

How does the Long Count work?

The Long Count calendar is a count of days since the Mayan date of creation, which is August 11, 3114 BCE in the proleptic Gregorian calendar or September 6, 3114 BCE in the proleptic Julian calendar.

It uses a modified base-20 system to represent this number, with each “digit” counting from 0 up to 19, except for the second last “digit,” which counts from 0 to 17. Typically, five numbers are shown, separated by dots, but in theory, more numbers could be used for dates in the distant future.

For example, the date 13.0.0.0.0 represents exactly 13×20×20×18×20 = 1 872 000 days since the date of creation, which is December 21, 2012 CE.

Each “digit,” of the Long Count have a name, from the rightmost: kʼin, winal, tun, kʼatun, bʼakʼtun, piktun, kalabtun, kʼinchiltun, alautun, hablatun. Terms from bʼakʼtun and beyond were invented by modern scholars and were not used by the classical Maya.