Rashi and Nakshatra Calculator — your Moon sign and birth star

Your rāśi — janma rāśi, or Moon sign — is the sign the Moon occupied at the moment you were born. Vedic astrology gives it more weight than the Sun sign: the daily and monthly readings, Sade Sati and the transit reading are all counted from it. It is not the rāśi that goes with the first letter of your name; that is a naming convention and says nothing about where your Moon was.

Two reasons. The sign most people know is the Sun sign; the rāśi is the Moon's sign. And Vedic astrology measures both against the sidereal zodiac, about 24° behind the tropical one Western astrology uses — so even the Sun sign usually moves back one.

The nakṣatra your Moon was in at birth. The zodiac is divided into 27 nakṣatras of 13°20′ each, and each into four pādas of 3°20′. Your nakṣatra sets the order of your planetary periods — its lord is the daśā your life began in — and it is the basis of kuṇḍalī matching.

Each of the 108 pādas has a syllable, and the tradition gives a child a name that begins with the syllable of the Moon's pāda at birth. The calculator shows yours and the other three of your nakṣatra. For Śravaṇa two conventions are in use — Khi, Khu, Khe, Kho, and Ju, Je, Jo, Gha — and both are shown.

Usually the birth time, sometimes the ayanāṁśa. The Moon moves about 13° a day — a pāda every six hours or so — so near a boundary a few minutes decide the answer. The calculator tells you how close yours was, so you know whether a small error in the recorded time matters.

Kuṇḍalī matching. The eight-point system (aṣṭakūṭa, out of 36) compares two nakṣatras on, among others, gaṇa (temperament, 6 points), nāḍī (constitution, 8 points — the heaviest) and yoni (physical and temperamental compatibility, 4 points).

Less than for most things. The Moon changes rāśi about every two and a quarter days, so the date alone is usually enough for the rāśi. The nakṣatra changes about once a day and the pāda every six hours, so the time matters more for those — and the ascendant changes about every two hours.