World Calendars
Aztec calendar today
The Mexica of Tenochtitlan counted days with two interlocking calendars: a 260-day ritual count and a 365-day solar year. Together they name every day in a cycle of 52 years.
7 Acatl (7 Reed)
chicome acatl - 20 Atlcahualo - ome acatl
20 Atlcahualo, year 2 Acatl (2 Reed)
- In the Gregorian calendar
- Wednesday 11 November 2026
- This day began
- At midnight, as Wednesday 11 November 2026 begins
- This day ends
- At midnight, as Thursday 12 November 2026 begins
- Year 2 Acatl (2 Reed) began
- Friday 23 October 2026
- Next new year
- Saturday 23 October 2027 (in 346 days)
- This year has
- 365 days in 18 months
- Day count
- Tonalpohualli - 260 days, 13 numbers x 20 day signs
- Solar year
- Xiuhpohualli - 18 veintenas of 20 days, plus 5 nemontemi days
- Year names
- 4 year bearers x 13 numbers - a cycle of 52 years
- Correlation used
- Caso - 13 August 1521 (Julian) = 1 Coatl, year 3 Calli
Next holidays in this calendar
346 days
Aztec New Year 2 Quiahuitl (2 Rain)
23 October 2027 · Aztec
How the Aztec calendar works
The tonalpohualli pairs a number from 1 to 13 with one of 20 day signs, so a day is written like "1 Coatl" (1 Snake). Both cycles turn at the same time, and the same pair comes back after 260 days. The days are also grouped into 20 trecenas of 13 days, each named after its first day. The same day count was used across Mesoamerica, and it runs in step with the Maya Tzolk'in.
| No. | Day sign | English |
|---|---|---|
| 1 | Cipactli | Crocodile |
| 2 | Ehecatl | Wind |
| 3 | Calli | House |
| 4 | Cuetzpalin | Lizard |
| 5 | Coatl | Snake (Serpent) |
| 6 | Miquiztli | Death |
| 7 | Mazatl | Deer |
| 8 | Tochtli | Rabbit |
| 9 | Atl | Water |
| 10 | Itzcuintli | Dog |
| 11 | Ozomahtli | Monkey |
| 12 | Malinalli | Grass |
| 13 | Acatl | Reed |
| 14 | Ocelotl | Jaguar |
| 15 | Cuauhtli | Eagle |
| 16 | Cozcacuauhtli | Vulture |
| 17 | Ollin | Movement (Earthquake) |
| 18 | Tecpatl | Flint |
| 19 | Quiahuitl | Rain |
| 20 | Xochitl | Flower |
The xiuhpohualli is the solar year: 18 veintenas of 20 days, then 5 nemontemi days that were thought to be unlucky. There is no leap day. Each year is named after a tonalpohualli day, and only four signs can name a year: Calli (House), Tochtli (Rabbit), Acatl (Reed) and Tecpatl (Flint). With 13 numbers that gives 52 year names. At the end of each 52-year cycle the Mexica held the New Fire ceremony, the "binding of the years".
The veintenas are listed below in the order used on this page, with their usual translations. Sources do not always agree on these meanings, and some of them are contested.
| No. | Veintena | Usual translation |
|---|---|---|
| 1 | Atlcahualo (also Cuahuitlehua) | The water ceases / the trees rise |
| 2 | Tlacaxipehualiztli | Flaying of men |
| 3 | Tozoztontli | Lesser vigil |
| 4 | Hueytozoztli | Greater vigil |
| 5 | Toxcatl | Dryness |
| 6 | Etzalcualiztli | Eating of cooked maize and beans |
| 7 | Tecuilhuitontli | Lesser feast day (of the lords) |
| 8 | Hueytecuilhuitl | Greater feast day (of the lords) |
| 9 | Tlaxochimaco (also Miccailhuitontli) | Giving of flowers / lesser feast of the dead |
| 10 | Xocotlhuetzi (also Hueymiccailhuitl) | The xocotl falls / greater feast of the dead |
| 11 | Ochpaniztli | Sweeping |
| 12 | Teotleco | The gods arrive |
| 13 | Tepeilhuitl | Feast of the mountains |
| 14 | Quecholli | Roseate spoonbill (precious feather) |
| 15 | Panquetzaliztli | Raising of banners |
| 16 | Atemoztli | Descent of water |
| 17 | Tititl | Stretching / contraction |
| 18 | Izcalli | Growth / sprout |
| - | Nemontemi (5 days) | "They fill up in vain" - not a veintena |
Variants and the method used here
The Aztec calendar is a reconstruction. Spanish and Nahuatl sources from the 1500s name days and years, but they do not agree on every detail, and historians still debate how the solar year lined up with the European calendar.
For the day count we use the correlation of Alfonso Caso, the one most cited by historians: the fall of Tenochtitlan on 13 August 1521 (Julian) was the day 1 Coatl in the year 3 Calli. In this correlation the Aztec day count matches the Maya Tzolk'in day for day.
For the solar year we count 365 days with no leap day, starting the year with Atlcahualo and ending it with the nemontemi. That puts 1 Atlcahualo on 13 February 1521 (Julian) and the new year of 2020 on 24 October. Other scholars disagree: Sahagún reported a year start on 2 February, Caso himself put Izcalli first, and Rafael Tena (INAH) argues for a leap day that keeps the new year on 13 February (Julian). Each choice gives different solar dates.
A short history
The Aztec calendar shares its basic structure with other calendars of Mesoamerica. Painted books such as the Codex Borbonicus record the full 260-day count, which priests used for divination. The Codex Borbonicus was made for the New Fire ceremony of the year 2 Acatl (1507), the last one before the Spanish arrived.
The Florentine Codex, written by Nahua scholars with Bernardino de Sahagún, records that the war for Tenochtitlan ended in the year 3 Calli on the day 1 Coatl. The famous Sun Stone, found in Mexico City on 17 December 1790, is often called the Aztec calendar, but it is a monument about cosmic time, not a working calendar.
Sources
How this site calculates the date: Alfonso Caso's correlation (13 August 1521 Julian = 1 Coatl, year 3 Calli): the 260-day tonalpohualli in step with the Maya Tzolk'in, and a 365-day year with no leap day that starts with Atlcahualo and ends with the five nemontemi.