Convert any Gregorian date (AD) into the classic Maya calendar systems: Long Count (baktun·katun·tun·uinal·kin), Tzolkʼin (260-day sacred round), Haabʼ (365-day vague year) and Lords of the Night (9-day cycle). Uses GMT correlation with additional Maya numeral glyphs visualization.
The Maya civilization developed one of the most sophisticated calendrical systems in human history. Unlike linear Western calendars, the Maya used interlocking cyclical calendars to record cosmological time, historical events, and ritual obligations. Our converter implements the three principal cycles: Long Count (linear count from a mythological starting point), Tzolkʼin (260-day divinatory calendar), Haabʼ (365-day agricultural calendar) and the Lords of the Night (9-day cycle). The convergence of Tzolkʼin and Haabʼ produces the Calendar Round (52 Haabʼ years ~ 18,980 days).
The GMT correlation (Goodman-Martínez-Thompson) correlates the Maya Long Count to the Julian calendar:
0.0.0.0.0 (4 Ajaw 8 Kumkʼu) = Julian Day Number 584283 = 11 August 3114 BCE (proleptic Gregorian).
Every Long Count position increments: 20 kin = 1 uinal; 18 uinal = 1 tun; 20 tun = 1 katun; 20 katun = 1 baktun.
Given a Gregorian date, we first compute its Julian Day Number (JD) using the standard astronomical algorithm for proleptic Gregorian. Then we compute Δ = JD - 584283 (the number of days elapsed since the Maya epoch). Long Count components are extracted via integer division:
Tzolkʼin date: (Δ + 3) modulo 13 gives number (1–13) and (Δ + 19) modulo 20 selects the day name from the 20 sacred names. Haabʼ date: (Δ + 348) modulo 365 returns the position in the vague year; the month index and day-of-month are derived using the Haabʼ month lengths (20 days for months 0–17, 5 days for month 18 Wayebʼ).
Lords of the Night (G‑series): A 9‑day cycle that repeats every 9 days. At the Maya epoch (0.0.0.0.0), the Lord of the Night is G9. Using the standard correlation: lord number = ((Δ + 8) % 9) + 1, giving values 1 through 9. This matches the G‑series order found in Classic period inscriptions (Berlin Codex).
The Tzolkʼin combines 20-day names (Imixʼ, Ikʼ, Akʼbal, Kʼan, Chikchan, Kimi, Manikʼ, Lamat, Muluk, Ok, Chuwen, Eb, Ben, Ix, Men, Kib, Kaban, Etzʼnabʼ, Kawak, Ajaw) with a numeration 1–13. This creates 260 unique day-signs, each with distinct ritual significance. The Haabʼ consists of 18 months of 20 days (Pop, Woʼ, Sip, Sotzʼ, Sek, Xul, Yaxkʼin, Mol, Chʼen, Yax, Sakʼ, Keh, Mak, Kʼankʼin, Muwanʼ, Pax, Kʼayab, Kumkʼu) plus a short month of 5 days (Wayebʼ), considered dangerous. Combined, the Calendar Round repeats every 52 Haabʼ years, a period central to Maya “New Fire” ceremonies.
| Maya Cycle | Length (days) | Example (epoch alignment) | Modern use |
|---|---|---|---|
| Long Count | Linear (13 Baktun ~ 5125 years) | 0.0.0.0.0 = 4 Ajaw 8 Kumkʼu | Historical chronology |
| Tzolkʼin | 260 | 4 Ajaw | Divination, naming ceremonies |
| Haabʼ | 365 | 8 Kumkʼu | Agricultural seasons, festivals |
| Lords of the Night | 9 | G9 (at epoch) | Nightly regents, lunar cycles |
Pakal the Great’s sarcophagus lid records his birth date: 9.8.9.13.0 (8 Ajaw 13 Pop). Using our converter, a researcher can verify the equivalent Gregorian date (March 23, 603 CE). The precision of the GMT correlation allows cross‑dating across numerous Maya sites, establishing absolute chronology for Classic period events (AD 250–900). Our tool replicates this scholarly method instantly.
Note on correlation alternatives: While GMT 584283 is used here (Goodman-Martínez-Thompson), some scholars proposed 584285 (Spinden) or 584280 (Böhm). The GMT correlation aligns best with astronomical tables in the Dresden Codex and radiocarbon data and remains the default in modern epigraphy. Our converter exclusively uses 584283 for consistency with the majority of published Maya dates.
The Lords of the Night are nine deities that govern each night in a 9‑day cycle. Often referred to as the G‑series in Maya inscriptions, they are associated with the lunar cycle and appear in the Palenque Cross Group. The cycle is synchronized with the Long Count: at the epoch (0.0.0.0.0) the Lord is G9. The index changes every day, and many stelae record the G‑series lord to refine historical records. Our converter calculates the lord number (G1 through G9) using standard correlation coefficients derived from the Berlin Codex: Lord number = ((Δ + 8) % 9) + 1. Knowing the Lord of the Night allows researchers to cross‑check dates and understand nocturnal rituals in Classic Maya cities.
List of Lords (classic order): G1 (Jaguar God of the Underworld), G2 (Stingray God), G3 (Young Maize God), G4 (Sun God), G5 (Moon Goddess), G6 (God of Dawn), G7 (God of the North), G8 (God of the South), G9 (God of the Center). The index shown in this converter follows the standard Thompson numbering.