Why it shifts
Western astrology puts 0° Aries at the spring equinox — the point where the Sun crosses the equator going north. That convention was set about two thousand years ago.
But Earth's axis wobbles like a spinning top, one full turn every 26,000 years or so. The equinox drifts backward against the actual constellations a little each year. Today it sits near Pisces, not Aries.
Western astrology keeps the original convention (the tropical zodiac). Vedic astrology follows the real positions of the stars (the sidereal zodiac). The correction between them is called the ayanamsa, and it is currently about 24.2°.
This service uses the Lahiri (Chitrapaksha) ayanamsa, the Indian government standard.
Conversion table for the 12 signs
If your birthday falls early in a sign (near the boundary), you shift back one sign. Later in the sign, you may stay. The exact answer needs your birth time.
| Western sign | Dates | Vedic |
|---|---|---|
| Aries | Mar 21 – Apr 19 | Pisces – Aries |
| Taurus | Apr 20 – May 20 | Aries – Taurus |
| Gemini | May 21 – Jun 21 | Taurus – Gemini |
| Cancer | Jun 22 – Jul 22 | Gemini – Cancer |
| Leo | Jul 23 – Aug 22 | Cancer – Leo |
| Virgo | Aug 23 – Sep 22 | Leo – Virgo |
| Libra | Sep 23 – Oct 22 | Virgo – Libra |
| Scorpio | Oct 23 – Nov 21 | Libra – Scorpio |
| Sagittarius | Nov 22 – Dec 21 | Scorpio – Sagittarius |
| Capricorn | Dec 22 – Jan 19 | Sagittarius – Capricorn |
| Aquarius | Jan 20 – Feb 18 | Capricorn – Aquarius |
| Pisces | Feb 19 – Mar 20 | Aquarius – Pisces |
The bigger difference: the Moon, not the Sun
The one-sign shift is not even the important part. When Western astrology asks "what sign are you?", it means the Sun. Vedic astrology answers the same question with the Moon.
The Sun stays in a sign for about a month, so everyone born in the same month shares a sign. The Moon moves 13° a day and changes section every two and a half days. And India divides that path into 27 sections, not 12.
So the base types in Vedic astrology number 27, not 12, and people born on the same day split by the hour. That is why this service asks for your birth time.
So which one is right?
Neither is wrong; they measure different things. A Western sign says "where in the season," a Vedic sign says "where among the actual stars." Both systems have been in use for over two thousand years.
Vedic is simply the less familiar one, so it tends to say things you have not heard before — the same reason a new system often surfaces new material.
Frequently asked
So what is my real sign?
Both are real. Western gives you a season-based sign, Vedic a star-based one. They use different coordinate systems; neither is an error. Within Vedic astrology, though, the Sun sign matters less than the birth star — which of 27 lunar sections the Moon occupied.
What about Ophiuchus, the 13th sign?
That comes from redrawing sign boundaries by astronomical constellation borders, which puts 13 constellations on the ecliptic. Astrology divides the sky into 12 equal parts, so it never matched the real constellation sizes to begin with. Vedic astrology also uses 12 equal parts — plus a 27-part division on top.
Can I convert without a birth time?
The Sun sign is nearly certain without a time; only births on a boundary day need it. The 27 birth stars are a different matter — they follow the Moon, so without a time about one in four would differ.
Just your date of birth. 30 seconds.