Zodiac Decans: Find Your Decan & All 36 Explained
What is a decan and which one are you? Find yours by birth date, get a full reading for every sign, and learn the story behind the 36 decans.
What is a decan?
The zodiac is a circle of 360 degrees, and each of the twelve signs takes up exactly 30 degrees of it. A decan (sometimes called a decanate) divides that 30-degree sign into three equal parts of 10 degrees each.
Three decans per sign across twelve signs gives you 36 decans ringing the whole sky. Each one tones the sign a little differently, like three shades of the same color. Your Sun sign tells you the broad strokes. Your decan sharpens the picture.
The word itself comes from the Greek dekanoi, built on deka, meaning ten, the same root behind decade. Below is a quick look at Aries split into its three decans. Every sign works the same way.
Example, Aries
Pure, headlong, pioneering
Warmer, prouder, more performative
Restless, far seeing, adventurous
Decans, sign by sign
What is a decan and which one are you? Find yours by birth date, get a full reading for every sign, and learn the story behind the 36 decans.
How decans are ruled
If you have ever seen your decan given one planet on one site and a different planet on another, here is why. More than one tradition is in use, and each assigns rulers its own way.
The Faces, Traditional
Ptolemaic planetary order
The older system hands each decan to one of the seven classical planets in what is called the descending Ptolemaic order, also known as the Chaldean order. The planets run from slowest to fastest, and the decans are handed out beginning with Mars. This is the system of the faces, the version used for talismans and astrological magic across the medieval and Renaissance worlds.
Because 36 does not divide evenly by seven, each planet rules five decans, except Mars, which rules six and bookends the circle at the end of Pisces and the start of Aries.
The Triplicities, Modern
Element based sub rulers
The popular modern system keeps the first decan with the sign’s own ruler, then sub rules the second and third decans by the other two signs of the same element. It is the version you will meet in most contemporary writing, and the one this page’s finder uses.
So an Aries born in the third decan carries a Sagittarius and Jupiter flavor, even though Mars still rules the sign as a whole.
A third approach, proposed by the Roman poet Manilius, simply assigns the signs to the decans in zodiacal order. It stayed a footnote in the West but became a working part of Indian astrology, where the decan lives on as the drekkana. None of these is the single true decan. They are parallel traditions, and which one you use depends on the kind of astrology you practice.
A history written in stars
The decans are far older than the horoscope columns they live in now. They began as a clock, then traveled across the ancient world, taking on new meaning in every civilization they touched.
Ancient Egypt, from the 3rd millennium BCE
A clock made of stars
For nearly two thousand years the decans were the backbone of Egyptian timekeeping, sacred and everyday alike. They were 36 star groups whose risings divided the night into hours and the year into roughly ten day weeks. Thirty six tens make 360, a near perfect circle of days, with five extra days left over outside the wheel and given to five great gods born of Nut, the goddess of the night sky.
The earliest evidence survives inside royal tombs, painted on coffin lids of the 21st century BCE as part of the spells that carried a pharaoh safely into the next world. The decans were never shown as earthly events like the flooding of the Nile, but as the gods believed to set those events in motion.
A flaw in the clock
Why the star lists kept changing
The system rested on fixed stars, but the sky slowly drifts. Through precession the marker stars slipped about ten days every seven centuries, and a calendar of 365 days lost a further quarter day each year. Over so long a span the anchors had to be reset again and again. More than fifty different decan lists survive, sorted into five families, which is why no single Egyptian decan can claim to be the original.
Hellenistic Egypt, 1st century BCE
Pinned to the zodiac
After Alexander’s conquest, Greek and Egyptian and Babylonian star lore fused in Alexandria, and a recognizable astrology was born. The decans were pried loose from the stars and pinned to the steady 360 degree zodiac, ten degrees each, three to a sign. Their Greek name, dekanoi, simply means the tens.
Here the planets took over from the old gods. Most texts assigned the decans to the seven planets in the descending Ptolemaic order, starting with Mars, giving the faces their lasting form. One astrologer, Manilius, instead handed them to the signs in order, the seed of the later Indian drekkana. In the magical and Hermetic writings of the age the decans also lived on as named spirits and daimones, each governing a part of the body and a slice of fate.
Medieval & Renaissance Europe
Talismans and images
Arabic scholars preserved and expanded the decan tradition, then passed it into Latin Europe. The magic manual Picatrix, and later Cornelius Agrippa, catalogued an image for each of the 36 faces, pictures to be carved at the right astrological moment to draw down a specific power. Decanic figures even reached the painted frescoed walls of the age, from grimoires to grand frescoes.
Today
Nuance for the modern chart
Two threads survive. The older planetary faces still appear in traditional and magical astrology, while the element based system dominates popular writing. Either way the purpose is the one it has always been: to find the finer grain inside a sign, and to explain why no two people of the same sign are quite alike.
Decan questions, answered
What is a decan in astrology?
A decan is a 10 degree slice of a zodiac sign. Each sign covers 30 degrees, so it splits into three decans of 10 degrees each, which makes 36 decans across the whole zodiac. Your decan refines your Sun sign by pointing to which third of the sign you were born in.
How many decans are there?
There are 36 in total: twelve signs times three decans each. The number goes back to ancient Egypt, where 36 star groups divided the year into roughly ten day weeks.
How do I find my decan?
Find your Sun sign from your birth date, then see where the date falls within it. The first ten days are the first decan, the next ten the second, the last ten the third.
What is the difference between my zodiac sign and my decan?
Your sign is the broad 30 degree band the Sun was in at your birth. Your decan is the narrower 10 degree slice within it. The sign sets the theme and the decan adds nuance, which is why two people of the same sign can feel quite different.
Why do different sources give my decan a different ruling planet?
Because more than one decan system exists. The traditional faces assign planets in Ptolemaic, while the modern system sub rules each decan by the next sign of the same element. Neither is the single correct one. See how decans are ruled for the full picture.
Are decans the same as the drekkana in Vedic astrology?
They share the same root idea of dividing a sign into thirds. In Vedic astrology the decan is called the drekkana and is one of the most used divisional charts. Each tradition developed its own rulers and imagery over time.
What if I was born on a cusp?
Sign and decan boundaries fall at an exact moment that shifts slightly each year. If your birthday lands within a day of a boundary, only a chart cast for your exact time and place can say for certain which decan holds your Sun.