The calendars of these two peoples were basically the same, but there were a few differences.
They were divided into eighteen months of twenty days each, with five intercalary days in regular years. There were a 260-day sacred calendar and a 365-day calendar. The two began on the same day every fifty-two years.
The thirteen-day period was represented numerically with dots; and the twenty-day period, by symbolic figures. The names varied between the Mayan and Aztec calendars. However, the two systems were very accurate, dating to about 3300 BCE.
The Maya named their days after local gods. Thus, they may have differed from one area to another. The Aztecs gave their days various names, which, likewise, may have differed from one area to another. The Aztecs did not name the intercalary days since they were considered to be unlucky.