How to use it
- Type your birth date and your birth time, as accurately as you can.
- Enter your Time zone as hours from UTC, for example 5.5 for India or 3 for Istanbul in summer.
- Read Moon sign (rashi), Nakshatra and its Pada.
- Open How the Moon sign and nakshatra are worked out to follow the steps, or the table to see all 27 nakshatras.
The sidereal zodiac and the ayanamsa
The Western zodiac counts from the spring equinox (the tropical zodiac). The Vedic zodiac counts from a fixed star, so it lies behind the tropical one by a slowly growing angle called the ayanamsa. The Lahiri ayanamsa, the one most used in India, is 23 degrees 15 minutes at 0h UT on 21 March 1956, the epoch the Indian Calendar Reform Committee chose, and it grows by about 50.24 seconds of arc a year.
The page takes the Moon's tropical longitude from astronomy-engine, a published open-source astronomy library, and subtracts the ayanamsa of the same moment. That gives the sidereal longitude, from which the rashi and the nakshatra follow.
sidereal = tropical Moon − ayanamsa
rashi = floor(sidereal ÷ 30) + 1
nakshatra = floor(sidereal ÷ 13° 20′) + 1
pada = floor(fraction of the nakshatra × 4) + 1Rashis, nakshatras and padas
The twelve rashis are the signs of the sidereal zodiac: Mesha (Aries) to Meena (Pisces). The 27 nakshatras are the lunar stations, each 13 degrees 20 minutes long and divided into four padas of 3 degrees 20 minutes. Each nakshatra has a lord, one of nine planets that repeat through the list: Ketu, Venus, Sun, Moon, Mars, Rahu, Jupiter, Saturn and Mercury.
Time, place and what the result is not
The Moon moves about 13 degrees a day, roughly one nakshatra. A birth time that is wrong by a few hours can therefore change the nakshatra or the pada, so enter the time as exactly as you can. The time zone must be the offset that applied at the birth place on that date, including summer time.
The rashi, the nakshatra and their lords are Vedic tradition. They are offered for entertainment and reflection and do not predict a person's life.
Worked example: 15 June 1990, 12:00 in UTC+5:30
The birth moment is 12:00 at UTC+5:30, which is 06:30 UTC. The tropical Moon is at 342.31°. The Lahiri ayanamsa, 34.23 years after 1956 at 50.2388″ a year, is 23.7278°. The sidereal Moon is therefore 342.31 − 23.73 = 318.58°.
318.58 ÷ 30 = 10.62, so the Moon is in the eleventh rashi, Kumbha (Aquarius), 18.58° into it. 318.58 ÷ 13.3333 = 23.89, so the nakshatra is the twenty-fourth, Shatabhisha, whose lord is Rahu. The fraction 0.89 × 4 = 3.57 gives pada 4.
| Part | Working | Result |
|---|---|---|
| Tropical Moon | astronomy-engine, 15 June 1990, 06:30 UTC | 342.31° |
| Lahiri ayanamsa | 23° 15′ + 34.23 years × 50.2388″ | 23.7278° |
| Sidereal Moon | 342.31 − 23.73 | 318.58° |
| Moon sign (rashi) | 318.58 ÷ 30 = 10.62 | Kumbha (Aquarius) |
| Nakshatra and pada | 318.58 ÷ 13.3333 = 23.89; fraction 0.89 × 4 | Shatabhisha (Rahu), pada 4 |
Frequently asked questions
What is the difference between the Vedic and the Western zodiac?
The Western zodiac starts at the spring equinox and is called tropical; the Vedic zodiac is sidereal and starts from a fixed point among the stars. The two differ by the ayanamsa, which is about 24 degrees today, so a Western sun sign and a Vedic Moon sign of the same date are often different signs.
Why does the time of birth matter so much?
The Moon moves about 13 degrees a day, so in one day it passes through about one nakshatra. A time that is wrong by a few hours can change the nakshatra or its pada near a boundary.
What is the Lahiri ayanamsa?
It is the ayanamsa adopted by the Indian Calendar Reform Committee, defined as 23 degrees 15 minutes on 21 March 1956, with the precession added linearly from that date. It is the most common ayanamsa in India. Other ayanamsas give different values.
What does pada mean?
A pada is a quarter of a nakshatra, 3 degrees 20 minutes of the zodiac. The four padas of a nakshatra are numbered 1 to 4 in the order of the Moon's movement.
Who is the lord of a nakshatra?
Each nakshatra has a lord from a list of nine planets that repeats three times through the 27 nakshatras. Ashwini is ruled by Ketu, Bharani by Venus, and Revati by Mercury.
Does the calculator keep my birth details?
No. The Moon's position is calculated in your browser, and nothing you enter is sent to a server or stored.
Sources
- astronomy-engine, the open-source library for the Moon's position (MIT licence)
- Wikipedia: Ayanamsa, the Lahiri ayanamsa and its epoch
- Wikipedia: Nakshatra, the 27 lunar stations and their padas
Figures and text last checked on Tuesday, November 10, 2026.