longcount

Long Count is a regnal and numeral date system used by the Maya to record long spans of time as a continuous count of days from a fixed origin. It functions as a linear calendar that can be read independently of the ritual calendars and is commonly found on monuments and in inscriptions.

The Long Count uses five place values in a vigesimal (base-20) scheme, with a special 360-day unit. The units are k’in (1 day), uinal (20 days), tun (18 uinal or 360 days), katun (20 tun or 7,200 days), and baktun (20 katun or 144,000 days). A date is written as baktun.katun.tun.uinal.k’in, with k’in 0–19, uinal 0–17, and tun, katun, baktun each 0–19. This structure allows the Maya to express dates far into the past or future with a compact five-number notation.

All Long Count dates are anchored to a fixed starting point, 0.0.0.0.0, which is associated with a specific Julian Day Number under the GMT correlation. The most widely used correlation constant is 584283, placing 0.0.0.0.0 around August 11, 3114 BCE in the proleptic Gregorian calendar. For example, 13.0.0.0.0 corresponds to a date near December 21, 2012 under this correlation.

Historically, the Long Count was used alongside the 260-day Tzolk’in and 365-day Haab calendars to structure ritual and historical time. Today it is a central tool in Maya archaeology and epigraphy, enabling historians to convert inscriptions into absolute dates and to understand the chronology of Maya civilizations. Variations in correlation constants exist, but 584283 remains the standard for most academic work.

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