How many days are in the Aztec solar calendar, the xiuhpohualli? It contains 365 days.
The Nahuatl name xiuhpohualli means “year count.” It was the civil, agricultural, and ceremonial calendar used by the Mexica and other Nahua peoples of central Mexico. Its structure combined 18 periods of 20 days each with an extra five-day period called nemontemi, producing 365 days in total.
The xiuhpohualli worked alongside the 260-day tonalpohualli, or ritual day count. The two cycles interlocked, and the same combination of calendar dates returned only after 52 solar years, a period often called the Calendar Round. Festivals and agricultural activities were organized around the year count.
The most common mistake is choosing 260 days: that number belongs to the tonalpohualli, not the solar calendar. Another tempting answer is 360, because 18 groups of 20 equal 360; the five nemontemi days complete the xiuhpohualli’s 365-day cycle. Scholars debate how leap-year corrections, if any, were handled.