Aztec Astrology: The Tonalpohualli, Day Signs, Birth Signs and Compatibility

Aztec astrology is far more fascinating than the simplified “Aztec zodiac signs” often found online. Behind the modern interpretations lies the Tonalpohualli, a 260-day divinatory calendar used in ancient Central Mexico to interpret time, destiny, personality, auspicious moments, and even relationships.

Your birth was not associated with just one zodiac-style symbol. A day carried a combination of a number, a day sign, and a place within a 13-day period, creating layers of meaning that specialists could interpret.

And relationships were part of the story too. Surviving Mesoamerican manuscripts contain marriage almanacs used to evaluate the possible fortunes of a union. So what might your birthday reveal?

What Is Aztec Astrology?

“Aztec astrology” is a convenient modern term, but it should not be imagined as a direct equivalent of Western astrology. The historical system was deeply connected to calendrical divination.

One of its foundations was the Tonalpohualli, a cycle of 260 days that repeated continuously. The Metropolitan Museum of Art describes the Tonalpohualli specifically as a 260-day divinatory calendar.

Rather than dividing people into 12 Sun signs, the system combined 20 recurring day signs with numbers from 1 through 13. That creates:

20 day signs × 13 numbers = 260 unique named days

The number and sign moved together through the cycle. After 1 Crocodile came 2 Wind, then 3 House, and so on.

Discover Your Aztec Sign

Curious about your Aztec sign and relationship compatibility? Keep reading to understand how the system works, then use the Aztec Astrology calculator below to reveal your birth sign, explore your personality reading, and then add your partner’s birth date to discover your compatibility.

The 20 Aztec Day Signs

The traditional system contained 20 signs rather than the familiar 12 signs of Western astrology.

Nahuatl name	Common English name
Cipactli	Crocodile
Ehecatl	Wind
Calli	House
Cuetzpalin	Lizard
Coatl	Serpent
Miquiztli	Death
Mazatl	Deer
Tochtli	Rabbit
Atl	Water
Itzcuintli	Dog
Ozomahtli	Monkey
Malinalli	Grass
Acatl	Reed
Ocelotl	Jaguar
Cuauhtli	Eagle
Cozcacuauhtli	Vulture
Ollin	Movement
Tecpatl	Flint
Quiahuitl	Rain
Xochitl	Flower

These signs should not simply be treated as 20 replacements for Aries, Taurus, Gemini, and the rest. Their significance depended on the larger calendrical and divinatory context in which they appeared.

Your Aztec Birth Sign Was More Than a Symbol

This is where the system becomes much more interesting.Someone born on 1 Crocodile, for example, could be interpreted through the qualities associated with Crocodile, the number 1, and the corresponding trecena, or 13-day period.

Someone born the following day, 2 Wind, shared that trecena but had a different day sign and number. Elizabeth Hill Boone notes that a person’s nature and inclinations were understood through these combined augural meanings. A simple way to visualize it is:

Layer	What it added
Day Sign	Symbolic identity of the day
Number 1–13	Another augural quality
Trecena	13-day divinatory context
Almanacs	Additional interpretations for particular situations

So asking “What is my Aztec sign?” is only the beginning.

Did Your Birth Day Influence Your Destiny?

This is one area where the comparison with a horoscope becomes more appropriate. Historical sources connect the day of birth with character and destiny. Research into the Codex Borbonicus and colonial Nahua sources notes prognostications concerning people born under different signs and trecenas.

A birth day could therefore carry favorable, unfavorable, or mixed implications. But this was not necessarily an unavoidable sentence. Divination was an interpretive practice involving specialists, calendars, images, symbols, and multiple interacting factors.

That complexity is important because modern online “Aztec zodiac” lists often reduce an elaborate system to one animal and several personality traits.

Aztec Love and Marriage Compatibility

Here things become particularly interesting. Marriage compatibility wasn’t simply invented by modern astrology websites. Surviving pre-Columbian divinatory codices contain marriage almanacs that associated calendrical information with predictions about relationships.  They could indicate whether a potential union appeared happy and successful, difficult, challenging, or disastrous. Some scenes even addressed children.

Versions survive in the Codex Borgia, Codex Laud, and Codex Vaticanus B, reflecting a broader divinatory tradition shared across parts of Central and southern Mexico. One particularly intriguing method used the birth-day numbers of two people.

Because each person’s day number ranged from 1 to 13, adding the two together produced a compatibility number between 2 and 26.

Example	Combined number
Day 3 + Day 2	5
Day 8 + Day 6	14
Day 10 + Day 9	19
Day 13 + Day 11	24

And those totals could lead to remarkably different images.

What Did the Marriage Numbers Mean?

The surviving almanacs weren’t simple “80% compatible” charts. Their imagery could tell a miniature story about the relationship. For number 5, a flowering tree appears between the man and woman, interpreted as a symbol of abundance.

At 14, a scorpion appears between the couple while the man turns away—suggesting a painful or harmful relationship. At 19, the couple exchange precious objects and the imagery points toward a much more favorable union. Number 24, by contrast, contains imagery associated with deception, infidelity, and conflict.

Importantly, these readings could be nuanced. A number was not necessarily universally “good” or “bad”; different symbols could point toward different aspects of married life.

So what story would the ancient marriage almanacs tell about you and your partner? Use our Aztec Astrology calculator below to discover your signs and reveal the symbolism behind your compatibility.

The Codex Borgia and the Survival of Aztec Divination

Much of what makes this subject so fascinating survives because of painted manuscripts. The famous Codex Borgia belongs to a group of pre-Columbian divinatory codices containing sophisticated calendrical almanacs.

Related marriage material survives in the Laud and Vaticanus B codices. However, calling all of this simply “Aztec astrology” hides an important detail. These traditions were not exclusively Aztec.

Evidence points to a shared Mesoamerican divinatory culture, with related ideas documented among Nahua/Aztec, Mixtec, Zapotec, and other communities of Central and southern Mexico. That makes the historical story much richer than a single civilization inventing a zodiac.

Aztec Astrology vs. Western Astrology

The two systems both connect birth timing with meaning, but their structures are very different.

Aztec / Tonalpohualli	Western Astrology
260-day divinatory cycle	Zodiac based on 12 signs
20 recurring day signs	12 zodiac signs
Numbers 1–13	Planets and zodiacal degrees
13-day trecenas	Houses and planetary aspects
Calendrical divination	Natal horoscope
Marriage almanacs	Synastry and composite charts

Western astrology asks where planets were positioned when you were born. Tonalpohualli divination instead places birth within a repeating sacred/divinatory calendar. They are therefore better understood as different systems that happen to share an interest in the meaning of birth timing.

Is the Modern Aztec Zodiac Historically Accurate?

Not always. Many modern “Aztec horoscope” systems turn the tradition into a small collection of animal or symbolic personality signs. Those systems can be fun, but they should not automatically be presented as literal reconstructions of pre-Columbian divination.

The historical tradition was considerably more complicated. Our Aztec Horoscope therefore combines a modern, accessible symbolic personality experience with clearly identified inspiration from the historical Tonalpohualli tradition.

The compatibility section draws particularly on documented marriage-almanac concepts while adapting them into an interactive modern reading. That distinction lets us explore an extraordinary tradition without pretending that a modern web calculator is an ancient manuscript.

Conclusion

Aztec astrology becomes far more interesting once you look beyond the idea of a simple zodiac sign. The Tonalpohualli connected 20 day signs, 13 numbers, trecenas, divinatory imagery, birth prognostications, and even marriage readings into a remarkably sophisticated system.

Your birth sign is therefore a doorway rather than the whole story. Discover your Aztec archetype, then add your partner’s birth date to see where your two symbolic paths meet.

FAQ

How many Aztec zodiac signs are there?

The historical Tonalpohualli contains 20 recurring day signs, each combined with numbers from 1 to 13 across a 260-day cycle.

What is the Tonalpohualli?

It is a 260-day Mesoamerican divinatory calendar used to interpret the qualities and fortunes associated with particular days.

Did the Aztecs believe your birthday affected your personality?

Historical sources associate the day of birth and its calendrical qualities with a person’s character, inclinations, and future prospects.

Did the Aztecs use compatibility for marriage?

Marriage divination is documented. Surviving almanacs assessed potential unions using calendrical information, including a system based on the combined day numbers of the prospective partners.

Is Aztec astrology the same as Mayan astrology?

No. They belong to related Mesoamerican calendrical traditions and share important structural features, including 260-day cycles, but they developed within different cultural and linguistic contexts.

Can I calculate my Aztec sign from my birthday?

Yes. Use the Aztec Horoscope Calculator above to turn your birth date into an accessible modern reading and then explore compatibility by adding your partner’s birth date.