Every day has a number
The Long Count is a place-value tally of days elapsed since a mythological era-base — 11 August 3114 BCE in the proleptic Gregorian calendar. It is mostly base-20, with one deliberate irregularity: 18 winals, not 20, make a tun, pulling the third place close to a 360-day year.
How the units nest
Read right to left: k'in, winal, tun, k'atun, b'ak'tun. The first five places carry ordinary Classic dates; the larger units appear mainly in Distance Numbers and mythological reckonings.
Distance Numbers
Maya scribes moved between dates by adding or subtracting a Distance Number — itself written in the same place-value units. Enter a start date and a Distance Number to step forward or back.
The 819-day count
Alongside the Long Count, Tzolk'in and Haab', many Classic inscriptions carry an 819-day count — 819 = 7 × 9 × 13, binding three sacred numbers. Each station is tied to one of the four directions and its colour, cycling East → North → West → South, so the full directional cycle runs 4 × 819 = 3,276 days.
Its purpose is debated — a planetary or ritual almanac keyed to the world-directions is the leading reading. This tool anchors a station on the era-base for illustration; real inscriptions cite the specific station preceding their date.
The lunar glyphs
A full Classic Initial Series date rarely stops at the Calendar Round. It continues with the Supplementary Series: the Lord of the Night (Glyph G) and its partner Glyph F, then the lunar record — the moon's age, which lunation of a six-month cycle it is (Glyph C), and whether that lunation was assigned 29 or 30 days.
The values below are an astronomical approximation from a modern synodic month, shown to convey the kind of information the glyphs carried — not a reconstruction of the specific Classic scribal value, which used its own lunar tables.