Mayan Calendar Converter

The Mayan Long Count calendar is an absolute chronological system that counts the number of days elapsed since the mythical Maya creation date of August 11, 3114 BCE (in the Gregorian calendar). Unlike the cyclical Tzolk'in and Haab' calendars, the Long Count uniquely identifies any single day across a great cycle of approximately 5,125 years. A date is written as five numbers separated by dots: Baktun.Katun.Tun.Winal.K'in.

The Long Count is built from five nested units of time: K'in (1 day), Winal (20 K'in = 20 days), Tun (18 Winal = 360 days), Katun (20 Tun = 7,200 days), and Baktun (20 Katun = 144,000 days). A full Great Cycle is 13 Baktun, or 1,872,000 days — roughly 5,125 solar years.

The Tzolk'in is the 260-day sacred calendar of the Maya, created by combining a cycle of 20 named days (such as Imix, Ik', Akbal) with a cycle of 13 numbers (1–13). Each combination is unique, producing 260 distinct day signs used for ritual, divination, and naming. The Tzolk'in and Haab' calendars together create the 52-year Calendar Round.

The Haab' is the Maya 365-day solar calendar made up of 18 months of 20 days each (360 days total) plus a short month called Wayeb' of 5 extra days. It closely approximates the solar year and was used for agricultural and civic purposes. A Haab' date is written as a day number (0–19) followed by the month name.

This calculator uses the GMT (Goodman-Martinez-Thompson) correlation constant of 584,283, the most widely accepted constant among Maya scholars today. It links the Mayan day count to the Julian Day Number, allowing accurate conversion between Gregorian and Mayan dates. Different constants (such as Spinden's 584,281) yield slightly different results.

December 21, 2012 marked the completion of the 13th Baktun in the Mayan Long Count, written as 13.0.0.0.0 — the end of a Great Cycle of approximately 5,125 years that began in 3114 BCE. While popular culture predicted apocalyptic events, Maya scholars and the Maya people themselves generally viewed it as the completion of one great cycle and the beginning of another, similar to how we celebrate a new millennium.

The Lords of the Night (also called the Nine Night Gods or G1–G9) are a cycle of nine deities that cycle through consecutive days in the Maya calendar. Each day is associated with one of the nine lords, and they were believed to govern the night hours. The Lord of the Night for any given date is determined by calculating the Maya day number modulo 9.

Yes — enter negative year values to represent BCE dates. For example, year -3114 corresponds to 3114 BCE, the approximate start of the Maya creation epoch. The conversion uses the proleptic Gregorian calendar for historical dates before the Gregorian reform of 1582 CE, so results for ancient dates are approximations based on astronomical back-calculation.