Mayan Haab Calendar Converter

The Haab divides the year into eighteen months of twenty days, giving 360, plus a closing period of five days called Wayeb. The days of each month are numbered zero to nineteen, and the zero is not a translation slip: the Maya counted the first day as the installation of the month, its seating, and only the next one took the number one.

Wayeb was the dangerous interval. Five days outside the structure of the months, when the boundaries between worlds loosened — a time for fasting, for staying home and for making no important decision. It is the same intuition found in other calendars with days left over outside the regular count, from the Egyptian calendar to the French complementary days.

The Haab has no leap day, so it slides against the solar year by about one day every four years. The Maya knew and did not correct it, because the Haab was not for predicting seasons: it turned alongside the 260-day Tzolk'in, and the pair only repeats after 18,980 days — the 52-year Calendar Round, which is the cycle that actually organised ritual life.