The zodiac
How twelve signs divide the zodiac
See the ecliptic cut into twelve equal 30° signs, find a sign from a longitude, and learn why signs differ from the constellations they are named after.
01 · Twelve equal parts
Cut the ecliptic into twelve equal signs.
The ecliptic is a full circle of 360°. Dividing it into twelve equal parts gives the signs, 30° each, numbered from Aries to Pisces. Here the circle is unrolled into a strip, and the Sun travels along it through one year.
A sign is a stretch of longitude, not a date range. The moment the Sun crosses from one sign into the next is a Sankranti, and the time it spends in one sign is a solar month.
02 · Patterns in the order
Three classifications repeat around the circle.
Each sign has an element, a mode and a ruling graha. They follow regular patterns: the four elements cycle every four signs, the three modes every three signs, and the rulers mirror each other on either side of Cancer and Leo.
These are classifications used when reading a chart. What each element, mode and ruler is taken to mean is explained in the zodiac signs guide.
03 · Signs and stars
Signs are equal. Constellations are not.
The constellations that share the signs’ names are patterns of stars covering areas of sky of very different sizes. Along the ecliptic, one spans about 8° and another about 44°. The ecliptic also passes through a thirteenth, Ophiuchus.
A sidereal sign takes its name from the constellation near it, but its boundaries are the equal 30° lines, not the edges of the star pattern.
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Twelve sectors of 30°
The zodiac is the ecliptic, the circle the Sun traces against the stars in a year. Every position on it is a longitude from 0° to 360°. The twelve signs divide that circle into equal sectors of 30° each, counted in order from the starting point.
| Number | Sign | Sanskrit name | Longitude |
|---|---|---|---|
| 1 | Aries | Mesha (मेष) | 0° to 30° |
| 2 | Taurus | Vrishabha (वृषभ) | 30° to 60° |
| 3 | Gemini | Mithuna (मिथुन) | 60° to 90° |
| 4 | Cancer | Karka (कर्क) | 90° to 120° |
| 5 | Leo | Simha (सिंह) | 120° to 150° |
| 6 | Virgo | Kanya (कन्या) | 150° to 180° |
| 7 | Libra | Tula (तुला) | 180° to 210° |
| 8 | Scorpio | Vrishchika (वृश्चिक) | 210° to 240° |
| 9 | Sagittarius | Dhanu (धनु) | 240° to 270° |
| 10 | Capricorn | Makara (मकर) | 270° to 300° |
| 11 | Aquarius | Kumbha (कुम्भ) | 300° to 330° |
| 12 | Pisces | Meena (मीन) | 330° to 360° |
Each range includes its start and stops just short of its end: 30° exactly is 0° Taurus, not 30° Aries.
Finding a sign from a longitude
Divide the longitude by 30. The whole number of thirties already completed gives the signs passed; the remainder is the degree within the current sign. For example, a longitude of 100° is three full signs plus 10°, so it is 10° Cancer, sign 4. A longitude of 275° is nine full signs plus 5°: 5° Capricorn, sign 10.
A chart writes the same position either way. The degrees guide shows the compact notation, and how rounding is handled near a boundary.
The Sun’s month in each sign
The Sun moves just under 1° a day, so it spends about a month in each sign. The moment it enters a new sign is a Sankranti, and its stay in one sign is a solar month. Makar Sankranti, for example, is the Sun’s entry into sidereal Capricorn.
The Sun moves a little faster in some parts of its orbit than others, so these months are not quite equal. Between 2026 and 2036 the Sun’s stay in a sidereal sign ranges from about 29.4 to 31.5 days. The signs themselves stay exactly 30° wide; only the time to cross them changes.
Elements, modes and rulers
Every sign has three classifications, and each follows a regular pattern around the circle:
- Element: Fire, Earth, Air and Water repeat in that order, starting at Aries. Aries, Leo and Sagittarius are the Fire signs.
- Mode: Movable, Fixed and Dual repeat in that order. Aries, Cancer, Libra and Capricorn are the movable signs.
- Ruler: the Moon rules Cancer and the Sun rules Leo. Moving outward from that pair in both directions, the rulers are Mercury, Venus, Mars, Jupiter and Saturn, so each of those five planets rules two signs, one on each side.
Because the elements repeat every four signs and the modes every three, no two signs share both. Fire with movable is only Aries; Fire with fixed is only Leo. The zodiac signs guide describes what each classification is taken to mean and links to each sign.
Signs are not constellations
The signs carry the names of constellations, but the two are different things. The International Astronomical Union recognises 88 constellations, each defined as an area of sky inside an agreed boundary. Those areas have irregular shapes and very different sizes.
Measured along the ecliptic, the narrowest of the zodiac constellations, Scorpius, covers only about 8°, while Virgo covers about 44°. The ecliptic also crosses Ophiuchus, between Scorpius and Sagittarius, which has no sign of its own. The equal 30° signs are a measuring system laid over the sky, not outlines of the star patterns.
A sidereal sign stays tied to the region of stars that gives it its name. A tropical sign starts from the March equinox instead and has slowly drifted away from those stars over the centuries. Both systems use the same twelve equal signs; they differ only in where 0° is placed. The sidereal and tropical comparison explains the difference.
Signs and houses
The sign numbers above are fixed: Aries is always sign 1. A Kundli’s houses are counted separately, starting from the rising sign, so Aries can be any house. The signs and houses guide explains how the two counts relate.
See the sign of each graha in the Positions table on the Kundli page, or explore another topic in Learn.