Birth details and astronomy
Moon Sign (Rashi) and Nakshatra: How They Are Calculated
By Match Kundli Editorial Team · Updated · 5 min read
Your Moon sign, or Rashi, is the sidereal zodiac sign the Moon occupied at the moment of birth, and your nakshatra is the one of 27 equal lunar mansions it occupied. Both come from a single number: the Moon's sidereal longitude, measured from 0° to 360° around the zodiac. Divide the circle into twelve parts of 30° to find the sign, into 27 parts of 13°20′ to find the nakshatra, and into 108 parts of 3°20′ to find the pada.
The arithmetic is simple once the longitude is known. Getting that longitude right is the hard part, and it is what the astronomical software does.
Step 1: find where the Moon was
Astronomers describe a planet's position along the zodiac by its ecliptic longitude. To find the Moon's longitude at birth, the birth date and time are first converted to universal time, and an ephemeris, a set of precise astronomical models, is used to calculate where the Moon stood at that instant.
This site uses Swiss Ephemeris, an astronomical library widely used in astrology software, through its built-in Moshier model. Its precision is a tiny fraction of a degree, far finer than the 3°20′ width of a pada, so the limiting factor in practice is how accurate the birth time is, not the astronomy.
Step 2: convert to the sidereal zodiac
The longitude an ephemeris gives first is measured from the spring equinox, which is the basis of the tropical zodiac used in Western astrology. Vedic astrology measures from a point fixed against the stars instead. The difference between the two, called the ayanamsa, is about 24°14′ in 2026 under the Lahiri system used in India and on this site.
So the sidereal longitude is simply the tropical longitude minus the ayanamsa. Why the two zodiacs drift apart, and why Lahiri is the Indian standard, is explained in sidereal versus tropical zodiac and the Lahiri ayanamsa.
Step 3: find the Moon sign
Each sign covers 30° of sidereal longitude, starting with Aries at 0°.
| Longitude | Sign (Rashi) | Longitude | Sign (Rashi) |
|---|---|---|---|
| 0° to 30° | Aries (Mesha) | 180° to 210° | Libra (Tula) |
| 30° to 60° | Taurus (Vrishabha) | 210° to 240° | Scorpio (Vrishchika) |
| 60° to 90° | Gemini (Mithuna) | 240° to 270° | Sagittarius (Dhanu) |
| 90° to 120° | Cancer (Karka) | 270° to 300° | Capricorn (Makara) |
| 120° to 150° | Leo (Simha) | 300° to 330° | Aquarius (Kumbha) |
| 150° to 180° | Virgo (Kanya) | 330° to 360° | Pisces (Meena) |
What remains after removing whole signs is the degree within the sign, which matters for Vashya koota in Sagittarius and Capricorn.
Step 4: find the nakshatra and pada
Each nakshatra spans 13°20′, beginning with Ashwini at 0° Aries. Because a sign holds two and a quarter nakshatras, nine of the 27 straddle a sign boundary.
| Nakshatra | Span | Nakshatra | Span |
|---|---|---|---|
| Ashwini | 0°00′ to 13°20′ Aries | Swati | 6°40′ to 20°00′ Libra |
| Bharani | 13°20′ to 26°40′ Aries | Vishakha | 20°00′ Libra to 3°20′ Scorpio |
| Krittika | 26°40′ Aries to 10°00′ Taurus | Anuradha | 3°20′ to 16°40′ Scorpio |
| Rohini | 10°00′ to 23°20′ Taurus | Jyeshtha | 16°40′ to 30°00′ Scorpio |
| Mrigashira | 23°20′ Taurus to 6°40′ Gemini | Mula | 0°00′ to 13°20′ Sagittarius |
| Ardra | 6°40′ to 20°00′ Gemini | Purva Ashadha | 13°20′ to 26°40′ Sagittarius |
| Punarvasu | 20°00′ Gemini to 3°20′ Cancer | Uttara Ashadha | 26°40′ Sagittarius to 10°00′ Capricorn |
| Pushya | 3°20′ to 16°40′ Cancer | Shravana | 10°00′ to 23°20′ Capricorn |
| Ashlesha | 16°40′ to 30°00′ Cancer | Dhanishta | 23°20′ Capricorn to 6°40′ Aquarius |
| Magha | 0°00′ to 13°20′ Leo | Shatabhisha | 6°40′ to 20°00′ Aquarius |
| Purva Phalguni | 13°20′ to 26°40′ Leo | Purva Bhadrapada | 20°00′ Aquarius to 3°20′ Pisces |
| Uttara Phalguni | 26°40′ Leo to 10°00′ Virgo | Uttara Bhadrapada | 3°20′ to 16°40′ Pisces |
| Hasta | 10°00′ to 23°20′ Virgo | Revati | 16°40′ to 30°00′ Pisces |
| Chitra | 23°20′ Virgo to 6°40′ Libra |
Within its nakshatra, the Moon's pada is the quarter it falls in: the first 3°20′ is pada 1, the next is pada 2, and so on to pada 4.
A worked example
Example 3 from our calculation engine uses a fictional boy born on 9 July 1991 at 23:45 IST in Bengaluru. The engine places his Moon at 24°28′ Taurus.
- Longitude. Taurus begins at 30°, so the sidereal longitude is 30° + 24°28′ = 54°28′.
- Sign. 54°28′ lies between 30° and 60°, so the Moon sign is Taurus.
- Nakshatra. 54°28′ is past the start of Mrigashira at 53°20′ (four spans of 13°20′), so the nakshatra is Mrigashira.
- Pada. The Moon is 1°08′ into Mrigashira, inside the first 3°20′, so it is pada 1.
That matches the "Taurus · Mrigashira-1" the result card shows for this birth. In the same way, the girl in Example 1, with her Moon at 13°43′ Capricorn, is 3°43′ into Shravana and therefore in pada 2.
Why your Moon sign usually differs from your Sun sign
The Sun sign that newspaper horoscopes use comes from the Sun's position, which changes sign once a month. The Moon goes round the whole zodiac in about 27⅓ days, so on any given birthday it can be in any sign. For most people the two are different, and in Vedic matching only the Moon sign counts.
There is a second source of difference: Western Sun signs use the tropical zodiac, so even a person's Sun sign often shifts by one sign when converted to the sidereal system.
Checking your own result
The result card shows each person's Moon sign and nakshatra-pada under their name. If you have a janam patri from the family priest, compare the two. A different pada, or occasionally a different nakshatra, usually points to one of three causes: a slightly different birth time, a different time zone assumption, or a different ayanamsa. Because 21 of the 36 points depend on the nakshatra, it is worth resolving before relying on Tara or Nadi results. Tips on getting the details right are in why birth time and birthplace matter.