Tools · Decan calculator
What decan am I? Your sign, cut into thirds
Every sign has three 10-degree decans, and your Sun, Moon and rising each sit in one. Find all three from your birthday, birth time, or a degree you already know.
Johann Gabriel Doppelmayr, Atlas Novus Coelestis, 1742
At a glance
Your decan is the 10-degree third of your sign: 0° to 10° is the 1st decan, 10° to 20° the 2nd, 20° to 30° the 3rd. Enter your birthday below to find your Sun decan in a second.
- Sun
- About 10 days per decan9.81 to 10.49 days on average, 1930 to 2040
- Moon
- About 18.2 hours per decan15.7 to 20.4 hours in 2026
- Rising
- 23 to 51 minutes per decanover New York; 17 to 57 over London
- Two systems
- Triplicity decans and Chaldean facesboth shown in the calculator
- First decan line of 2026
- Mar 20, 2026, 14:45 UTC0° Aries, the March equinox; 36 Sun decan crossings in 2026
Find your decansBirthday only, full chart, or a degree from your chart.
The idea
Two Scorpios walk into a party
Try this today
- Find your Sun decan with just your birthday, then read your sign's page. Notice whether your decan's description fits better than the generic sign one.
- Do the same for a friend whose personality never seemed to match their sign.
One is the quiet one in the corner reading everyone's body language. The other is the one who brought homemade food and is making sure nobody leaves hungry. Both are Scorpio Suns. Decans are one of astrology's oldest ways to explain that.
A sign covers 30° of the zodiac. Split it into three equal parts and you get three decans of 10° each: 0° to 10°, 10° to 20°, 20° to 30°. Twelve signs times three makes 36 decans around the whole circle.
Each decan gets a planetary "sub-ruler" that colours the sign. In the triplicity system most modern books use, a sign's three decans borrow from the three signs of its element, starting with itself. Scorpio's run Scorpio, Pisces, Cancer. Aries runs Aries, Leo, Sagittarius. So the second Scorpio above, the feeder, might well be a 3rd decan Scorpio, with a dash of Cancer.
Decans work for any placement, not only the Sun. Your Moon has a decan. So does your rising sign, your Venus, your Mars. That is why this calculator gives you three at once.
Sun decan
Why your Sun decan dates move by a day or two
Try this today
- Enter your birthday in the calculator. If it says "decan-line birthday", find your birth certificate time.
- Check a sibling's birthday too. Same family, often different decans.
Most decan charts online print one fixed set of dates. The Sun does not follow them exactly. We computed every Sun crossing of every decan line from 1930 to 2040, and the calendar date it happens on (in UTC) can vary across up to 3 different days for the same decan.
Two things cause the wobble. Our calendar has leap years, so the same moment of the solar year drifts by about six hours a year and jumps back every fourth February. And your time zone matters: a crossing late on one day in London is already the next day in Tokyo.
The decans are not equal in length either. The Sun spends 10.49 days on average in the Cancer 1st decan but only 9.81 in the Capricorn 1st. Earth moves fastest around early January, when it is closest to the Sun, so the Sun hurries through the decans of Sagittarius and Capricorn and lingers in Gemini and Cancer.
If your birthday is near a decan line, the calculator tells you, gives the exact moment of the crossing, and lets you add your birth time to settle it.
The sky behind it
Sun crossings computed with skyfield and JPL DE442, geocentric apparent longitude, tropical zodiac, UTC. In 2026 the Sun reaches 0° Aries on Mar 20, 2026, 14:45 UTC; timeanddate lists the 2026 March equinox at 14:46 UTC on March 20.
Moon decan
Your Moon decan: the one that needs a birth time
Try this today
- Ask a parent if you were born in the morning, afternoon or night. The calculator's Moon timeline turns that into an answer.
- Read your Moon decan alongside your Sun decan. Where do they agree?
The Moon is the fastest body in your chart. It crosses a whole decan in about 18.2 hours, and in 2026 that ranged from 15.7 to 20.4 hours depending on where the Moon was in its tilted, oval orbit. It crossed 482 decan lines in 2026 alone.
So if you only know your birth date, your Moon could be in one of two decans, sometimes three. Astrologers read the Moon as your emotional needs, what makes you feel safe, and the Moon's decan adds the same kind of nuance the Sun's does: a Cancer-decan Moon in Scorpio feels different from a Scorpio-decan one.
No birth time? Switch the calculator to "Sun, Moon & rising" and tick the unknown-time box. It lists every Moon decan of your birth day with the clock times, so a rough memory of "morning" or "after dinner" might be enough.
Rising decan
Your rising decan: minutes, not days
Try this today
- Run the calculator with your recorded birth time. If it flags your rising, try your rising sign page and see which decan description fits.
- No time at all? The rising sign without birth time tool shows every possibility across your birth day.
Your rising sign is whatever degree of the zodiac was climbing over the eastern horizon when you were born. The whole zodiac rises once a day, so a decan rises in well under an hour. How long exactly depends on the decan and on how far you were born from the equator.
We computed it. Over London, the Aries 1st decan rises in just 16.7 minutes, while the Leo 3rd takes 57.1. Over New York the range is 23.0 to 51.0 minutes; over Sydney, where the pattern flips, 26.0 to 48.4.
That is why a rising decan needs an accurate birth time. A hospital clock rounded to the nearest quarter hour can be enough to tip you into the next decan, especially for the fast-rising stretch around Pisces and Aries in the northern hemisphere. The calculator checks this for you: it tells you if moving your birth time by 30 minutes would change any of your three decans.
The sky behind it
Rising times are oblique-ascension intervals for each 10° of ecliptic, with the 2026 mean obliquity (23.4359°), converted to clock minutes. Checked against a minute-by-minute scan of the same Ascendant formula the calculator uses (largest difference 0.25 min).
Where it comes from
From Egyptian star clocks to tarot cards
Try this today
- Compare your two rulers in the calculator, triplicity and Chaldean. If they differ, read both as two sides of you.
- Look up your decan card. Many tarot readers use it as a personal card.
Decans are older than the zodiac signs as we use them. In Egypt they started as 36 groups of stars that rose one after another through the night, used to tell the hours. Tables of them painted on coffin lids, sometimes called diagonal star tables, date to the First Intermediate Period, more than four thousand years ago (Wikipedia: Decan; Diagonal star table). The famous Dendera zodiac, carved around 50 BCE and now in the Louvre, shows the decans alongside the twelve signs.
Hellenistic astrologers in Alexandria folded the 36 decans into the twelve signs as 10° thirds and gave them planetary rulers. One scheme became the Chaldean faces: the seven classical planets in the order Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon, starting with Mars at 0° Aries and cycling round. William Lilly printed it as the "face" column of his table of essential dignities in Christian Astrology (1647) (Essential dignity).
The triplicity system, where each decan borrows from a sign of the same element, is the one most modern Western books use, and it matches the drekkana of Indian astrology. The two systems agree on only 9 of the 36 decans.
In the late 19th century the Hermetic Order of the Golden Dawn tied each of the 36 decans to one of the numbered minor tarot cards, using the Chaldean face planets. That is why the calculator also shows you a card.
The calculator
Find your Sun, Moon and rising decans
Three ways in. Just a birthday gives your Sun decan, and flags it if the Sun changed decan that day. Full birth details give all three. Or type any degree from a chart you already have. Everything runs on your device; only the town search asks our server for coordinates.
What do you have?
Pick a date to see your Sun decan. Nothing is sent anywhere; it is worked out on your device.
More to read
Shorter reads. Each opens in place.
Two systems
Triplicity or Chaldean: which decan system is right?
Neither is provably right; they are two traditions. The triplicity system is simpler and is what most horoscope writers mean by "decan" today. The Chaldean faces are older in Western texts and are what traditional astrologers and Golden Dawn tarot use. This calculator shows both, so you can read each and see which rings truer.
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Every sign
Decan dates for all twelve signs
Typical dates for the 1st / 2nd / 3rd decan. Tap a sign for the full story.
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Aries: Mar 20 to Mar 29 / Mar 30 to Apr 9 / Apr 10 to Apr 19
Taurus: Apr 20 to Apr 29 / Apr 30 to May 9 / May 10 to May 20
Gemini: May 21 to May 30 / May 31 to Jun 10 / Jun 11 to Jun 20
Cancer: Jun 21 to Jul 1 / Jul 2 to Jul 11 / Jul 12 to Jul 22
Leo: Jul 23 to Aug 1 / Aug 2 to Aug 11 / Aug 12 to Aug 22
Virgo: Aug 23 to Sep 1 / Sep 2 to Sep 11 / Sep 12 to Sep 22
Libra: Sep 23 to Oct 2 / Oct 3 to Oct 12 / Oct 13 to Oct 22
Scorpio: Oct 23 to Nov 1 / Nov 2 to Nov 11 / Nov 12 to Nov 21
Sagittarius: Nov 22 to Dec 1 / Dec 2 to Dec 11 / Dec 12 to Dec 21
Capricorn: Dec 22 to Dec 30 / Dec 31 to Jan 9 / Jan 10 to Jan 19
Aquarius: Jan 20 to Jan 29 / Jan 30 to Feb 8 / Feb 9 to Feb 18
Pisces: Feb 19 to Feb 27 / Feb 28 to Mar 9 / Mar 10 to Mar 19
All 36 decans, computed
Typical birthdays are the most common Sun entry dates from 1930 to 2040 (UTC). The 2026 column gives the exact moment the Sun crosses each decan line.
| Decan | Typical birthdays | Triplicity (ruler) | Chaldean face | Golden Dawn card | Sun enters, 2026 |
|---|---|---|---|---|---|
| Aries 1st (0°-10°) | Mar 20 to Mar 29 | Aries (Mars) | Mars | Two of Wands | Mar 20, 2026, 14:45 UTC |
| Aries 2nd (10°-20°) | Mar 30 to Apr 9 | Leo (Sun) | Sun | Three of Wands | Mar 30, 2026, 16:58 UTC |
| Aries 3rd (20°-30°) | Apr 10 to Apr 19 | Sagittarius (Jupiter) | Venus | Four of Wands | Apr 9, 2026, 20:40 UTC |
| Taurus 1st (0°-10°) | Apr 20 to Apr 29 | Taurus (Venus) | Mercury | Five of Pentacles | Apr 20, 2026, 01:39 UTC |
| Taurus 2nd (10°-20°) | Apr 30 to May 9 | Virgo (Mercury) | Moon | Six of Pentacles | Apr 30, 2026, 08:04 UTC |
| Taurus 3rd (20°-30°) | May 10 to May 20 | Capricorn (Saturn) | Saturn | Seven of Pentacles | May 10, 2026, 15:49 UTC |
| Gemini 1st (0°-10°) | May 21 to May 30 | Gemini (Mercury) | Jupiter | Eight of Swords | May 21, 2026, 00:36 UTC |
| Gemini 2nd (10°-20°) | May 31 to Jun 10 | Libra (Venus) | Mars | Nine of Swords | May 31, 2026, 10:31 UTC |
| Gemini 3rd (20°-30°) | Jun 11 to Jun 20 | Aquarius (Uranus / Saturn) | Sun | Ten of Swords | Jun 10, 2026, 21:13 UTC |
| Cancer 1st (0°-10°) | Jun 21 to Jul 1 | Cancer (Moon) | Venus | Two of Cups | Jun 21, 2026, 08:24 UTC |
| Cancer 2nd (10°-20°) | Jul 2 to Jul 11 | Scorpio (Pluto / Mars) | Mercury | Three of Cups | Jul 1, 2026, 20:04 UTC |
| Cancer 3rd (20°-30°) | Jul 12 to Jul 22 | Pisces (Neptune / Jupiter) | Moon | Four of Cups | Jul 12, 2026, 07:45 UTC |
| Leo 1st (0°-10°) | Jul 23 to Aug 1 | Leo (Sun) | Saturn | Five of Wands | Jul 22, 2026, 19:13 UTC |
| Leo 2nd (10°-20°) | Aug 2 to Aug 11 | Sagittarius (Jupiter) | Jupiter | Six of Wands | Aug 2, 2026, 06:23 UTC |
| Leo 3rd (20°-30°) | Aug 12 to Aug 22 | Aries (Mars) | Mars | Seven of Wands | Aug 12, 2026, 16:47 UTC |
| Virgo 1st (0°-10°) | Aug 23 to Sep 1 | Virgo (Mercury) | Sun | Eight of Pentacles | Aug 23, 2026, 02:18 UTC |
| Virgo 2nd (10°-20°) | Sep 2 to Sep 11 | Capricorn (Saturn) | Venus | Nine of Pentacles | Sep 2, 2026, 10:53 UTC |
| Virgo 3rd (20°-30°) | Sep 12 to Sep 22 | Taurus (Venus) | Mercury | Ten of Pentacles | Sep 12, 2026, 18:07 UTC |
| Libra 1st (0°-10°) | Sep 23 to Oct 2 | Libra (Venus) | Moon | Two of Swords | Sep 23, 2026, 00:05 UTC |
| Libra 2nd (10°-20°) | Oct 3 to Oct 12 | Aquarius (Uranus / Saturn) | Saturn | Three of Swords | Oct 3, 2026, 04:44 UTC |
| Libra 3rd (20°-30°) | Oct 13 to Oct 22 | Gemini (Mercury) | Jupiter | Four of Swords | Oct 13, 2026, 07:51 UTC |
| Scorpio 1st (0°-10°) | Oct 23 to Nov 1 | Scorpio (Pluto / Mars) | Mars | Five of Cups | Oct 23, 2026, 09:37 UTC |
| Scorpio 2nd (10°-20°) | Nov 2 to Nov 11 | Pisces (Neptune / Jupiter) | Sun | Six of Cups | Nov 2, 2026, 10:08 UTC |
| Scorpio 3rd (20°-30°) | Nov 12 to Nov 21 | Cancer (Moon) | Venus | Seven of Cups | Nov 12, 2026, 09:16 UTC |
| Sagittarius 1st (0°-10°) | Nov 22 to Dec 1 | Sagittarius (Jupiter) | Mercury | Eight of Wands | Nov 22, 2026, 07:23 UTC |
| Sagittarius 2nd (10°-20°) | Dec 2 to Dec 11 | Aries (Mars) | Moon | Nine of Wands | Dec 2, 2026, 04:36 UTC |
| Sagittarius 3rd (20°-30°) | Dec 12 to Dec 21 | Leo (Sun) | Saturn | Ten of Wands | Dec 12, 2026, 00:57 UTC |
| Capricorn 1st (0°-10°) | Dec 22 to Dec 30 | Capricorn (Saturn) | Jupiter | Two of Pentacles | Dec 21, 2026, 20:50 UTC |
| Capricorn 2nd (10°-20°) | Dec 31 to Jan 9 | Taurus (Venus) | Mars | Three of Pentacles | Dec 31, 2026, 16:27 UTC |
| Capricorn 3rd (20°-30°) | Jan 10 to Jan 19 | Virgo (Mercury) | Sun | Four of Pentacles | Jan 10, 2026, 06:09 UTC |
| Aquarius 1st (0°-10°) | Jan 20 to Jan 29 | Aquarius (Uranus / Saturn) | Venus | Five of Swords | Jan 20, 2026, 01:44 UTC |
| Aquarius 2nd (10°-20°) | Jan 30 to Feb 8 | Gemini (Mercury) | Mercury | Six of Swords | Jan 29, 2026, 21:45 UTC |
| Aquarius 3rd (20°-30°) | Feb 9 to Feb 18 | Libra (Venus) | Moon | Seven of Swords | Feb 8, 2026, 18:28 UTC |
| Pisces 1st (0°-10°) | Feb 19 to Feb 27 | Pisces (Neptune / Jupiter) | Saturn | Eight of Cups | Feb 18, 2026, 15:51 UTC |
| Pisces 2nd (10°-20°) | Feb 28 to Mar 9 | Cancer (Moon) | Jupiter | Nine of Cups | Feb 28, 2026, 14:17 UTC |
| Pisces 3rd (20°-30°) | Mar 10 to Mar 19 | Scorpio (Pluto / Mars) | Mars | Ten of Cups | Mar 10, 2026, 13:57 UTC |
| Decan | New York | London | Sydney | Sun's average stay (days) |
|---|---|---|---|---|
| Aries 1st | 23.0 | 16.7 | 47.3 | 10.10 |
| Aries 2nd | 23.6 | 17.3 | 47.5 | 10.16 |
| Aries 3rd | 24.6 | 18.4 | 47.8 | 10.21 |
| Taurus 1st | 26.3 | 20.1 | 48.2 | 10.27 |
| Taurus 2nd | 28.5 | 22.6 | 48.4 | 10.32 |
| Taurus 3rd | 31.3 | 26.0 | 48.4 | 10.37 |
| Gemini 1st | 34.5 | 30.2 | 47.8 | 10.41 |
| Gemini 2nd | 38.1 | 35.3 | 46.6 | 10.45 |
| Gemini 3rd | 41.7 | 40.7 | 44.6 | 10.47 |
| Cancer 1st | 45.0 | 46.1 | 42.1 | 10.49 |
| Cancer 2nd | 47.7 | 50.6 | 39.3 | 10.49 |
| Cancer 3rd | 49.6 | 53.9 | 36.3 | 10.48 |
| Leo 1st | 50.6 | 55.9 | 33.5 | 10.46 |
| Leo 2nd | 51.0 | 56.9 | 31.1 | 10.43 |
| Leo 3rd | 51.0 | 57.1 | 29.1 | 10.40 |
| Virgo 1st | 50.7 | 57.0 | 27.5 | 10.35 |
| Virgo 2nd | 50.4 | 56.7 | 26.5 | 10.30 |
| Virgo 3rd | 50.3 | 56.6 | 26.0 | 10.25 |
| Libra 1st | 50.3 | 56.6 | 26.0 | 10.19 |
| Libra 2nd | 50.4 | 56.7 | 26.5 | 10.13 |
| Libra 3rd | 50.7 | 57.0 | 27.5 | 10.07 |
| Scorpio 1st | 51.0 | 57.1 | 29.1 | 10.01 |
| Scorpio 2nd | 51.0 | 56.9 | 31.1 | 9.96 |
| Scorpio 3rd | 50.6 | 55.9 | 33.5 | 9.92 |
| Sagittarius 1st | 49.6 | 53.9 | 36.3 | 9.88 |
| Sagittarius 2nd | 47.7 | 50.6 | 39.3 | 9.85 |
| Sagittarius 3rd | 45.0 | 46.1 | 42.1 | 9.83 |
| Capricorn 1st | 41.7 | 40.7 | 44.6 | 9.81 |
| Capricorn 2nd | 38.1 | 35.3 | 46.6 | 9.81 |
| Capricorn 3rd | 34.5 | 30.2 | 47.8 | 9.82 |
| Aquarius 1st | 31.3 | 26.0 | 48.4 | 9.84 |
| Aquarius 2nd | 28.5 | 22.6 | 48.4 | 9.86 |
| Aquarius 3rd | 26.3 | 20.1 | 48.2 | 9.90 |
| Pisces 1st | 24.6 | 18.4 | 47.8 | 9.94 |
| Pisces 2nd | 23.6 | 17.3 | 47.5 | 9.99 |
| Pisces 3rd | 23.0 | 16.7 | 47.3 | 10.04 |
All times are UTC. In the Americas the local date can be a day earlier; in Asia and Australia a day later.
Quick answers
What decan am I?
Find your Sun's degree in your sign: 0° to 10° is the 1st decan, 10° to 20° the 2nd, 20° to 30° the 3rd. The quickest way is to enter your birthday in the calculator above. If the Sun changed decan on your birthday, it tells you the exact moment so your birth time can settle it.
How do I find my Moon decan?
You need your birth date, and ideally your birth time and town, because the Moon changes decan about every 18.2 hours. Choose "Sun, Moon & rising" in the calculator. Without a time it lists each Moon decan of your birth day with clock times.
Is there a rising decan calculator without a birth time?
Not reliably. Your rising decan changes every 17 to 57 minutes over London (23 to 51 over New York), so it needs a birth time. Our rising sign without birth time tool shows every rising sign that was possible on your birth day.
What decan am I if I'm a Scorpio?
It depends on your Sun's degree: 0° to 10° Scorpio is the 1st (Scorpio) decan, 10° to 20° the 2nd (Pisces) decan, 20° to 30° the 3rd (Cancer) decan. Enter your birthday in the calculator or see the Scorpio decans page for typical dates and the 2026 and 2027 crossing times.
What is a decan in astrology?
A decan is a 10-degree third of a zodiac sign, so there are 36 around the zodiac. Each has a planetary sub-ruler that adds a flavour to the sign. The idea goes back to 36 star groups the ancient Egyptians used to tell time at night.
What's the difference between a decan and a cusp?
A decan is a fixed third of a sign, defined by degree. Being "on the cusp" is a loose term for being born near the line between two signs. Astronomically you are always in one sign or the other; the 3rd decan of one sign is simply the last stretch before the next.
Do decan dates change in 2026 and 2027?
Slightly. Each decan line falls on one of two or three calendar dates depending on the year and your time zone. In 2026 the first line, 0° Aries, is crossed on Mar 20, 2026, 14:45 UTC. The table above lists all 36 crossings for 2026, and every sign page has 2027 too.
Which decan system does this calculator use?
Both. It shows the triplicity decan (the sign and ruler most modern books use), the Chaldean face ruler from traditional astrology, and the Golden Dawn tarot card for the same 10 degrees.
