A Maya tzolk’in calendar cycle contains 260 days. It is formed by combining a sequence of 20 named days with a sequence of 13 numbers.
Each day advances both parts of the system: the day name moves through its 20-position cycle, while the number runs from 1 to 13 and then starts again. Because 20 and 13 have no common factor, every possible pairing takes 20 × 13, or 260 days, to appear once before the combination repeats.
The tzolk’in was not the Maya solar year. It was a sacred and ceremonial cycle used for divination, naming, rituals, and choosing auspicious dates. It operated alongside the 365-day haab’ calendar. Together, the two calendars created a Calendar Round in which the same combined date returned every 18,980 days, or 52 haab’ years. Several contemporary Maya communities in Guatemala continue to maintain related 260-day calendar traditions.