Tithi Calculator

A lunar day measured in degrees, not hours

In the Surya Siddhanta tradition the first tithi of the month lasts while the Moon is between 0° and 12° ahead of the Sun, the second while it is between 12° and 24°, and so on until the thirtieth closes at 360°, the next new moon. The names follow the count: Pratipada, Dwitiya, Tritiya, Chaturthi, Panchami, Shashthi, Saptami, Ashtami, Navami, Dashami, Ekadashi, Dwadashi, Trayodashi and Chaturdashi, with the fifteenth of the bright half called Purnima and the fifteenth of the dark half, the thirtieth overall, Amavasya.

Both bodies move at varying speeds, the Moon especially, so a tithi can run from about 19 to about 26 hours against an average a little under 24. The one in the worked example lasted from 18:49 one evening to 16:38 the next afternoon, just under 22 hours.

That irregularity is behind two calendar oddities, since a printed panchang names each civil day after the tithi current at sunrise: a short tithi can miss every sunrise and vanish from the calendar (kshaya), and a long one can catch two and name two days running (adhika or vriddhi).

Why a birth tithi is not a calendar date

Because tithis and civil days are out of step, the date on a birth certificate does not fix a tithi: almost every date holds the end of one and the start of the next, so a tithi by date of birth alone is usually a choice between two, and the birth time decides it. With the time left blank, the page checks 00:00 and 23:59 local time and shows both tithis when they differ — and only the civil weekday, since the vara turns on whether the birth came before sunrise.

The birthday that follows from the janma tithi moves too. The traditional birthday is the tithi's recurrence in the same lunar month as the birth, and since a lunar year runs about eleven days short of the solar one, with an extra month inserted every two and a half to three years, that day slides earlier through the Gregorian calendar and then jumps later. Families differ on which day to keep when the tithi does not hold at sunrise; the page gives the astronomy and leaves the custom to you.

Five limbs, and the sunrise rule for the vara

Panchanga means five limbs, and the calculator reports all five for the birth moment. The tithi is the first. The vara is the weekday. The nakshatra is the Moon's star, one of twenty-seven 13°20′ divisions of the zodiac, given with its pada. The yoga divides the sum of the Sun's and Moon's sidereal longitudes into twenty-seven parts of 13°20′, from Vishkumbha to Vaidhriti. The karana is half a tithi, six degrees of elongation, drawn from a set of eleven: seven that cycle through the month and four that occur once each.

The vara follows the Vedic day, which runs from sunrise to sunrise rather than midnight to midnight. A birth in the small hours before sunrise therefore belongs to the previous day's vara even though the civil calendar has already turned over. The page shows both the civil weekday and the vara, and applies the rule against the actual sunrise at the birthplace rather than a nominal six o'clock.

The worked example, limb by limb

At 05:30 on 13 December 1961 in Channarayapatna the Moon was about 66° ahead of the Sun, which places the birth in the sixth tithi of the bright half: Shukla Shashthi, printed by the engine as “Sukla Paksha Shasti”. That tithi began at 18:49:04 on 12 December and ended at 16:38:06 on the 13th, and 50.98% of it was still to run at the birth — almost exactly its midpoint.

Sunrise there that morning was at 06:40:53, so the birth came just over seventy minutes before it. The civil calendar says Wednesday; the Vedic vara is still Tuesday, Mangalavara. The other three limbs were the nakshatra Dhanishta, pada 3, the yoga Harshana, and the karana Kaulava, the first half of Shashthi, which gave way to Taitila at 05:42, less than a quarter of an hour after the birth.

A later birth on the same date would have had a different panchang on every count. By five that afternoon the nakshatra had passed to Shatabhisha (at 11:10), the yoga to Vajra (14:51) and the tithi to Shukla Saptami (16:38), so a child born then would have had a Wednesday vara, Saptami, Shatabhisha, Vajra and the karana Gara — five limbs, none shared with the 05:30 birth.

The engine's panchang gives the lunar month as Maargazhi, the Tamil name for Margashirsha, so a birth like this one has its tithi birthday each year on Margashirsha Shukla Shashthi, the day much of Karnataka keeps as Subramanya Shashthi.

Tithis at birth in the classical texts

Parashara takes up the birth tithi near the end of Brihat Parasara Hora Sastra, together with births in certain yogas and karanas and at the tithi gandanta — the junction where the fifth, tenth or fifteenth tithi gives way to the next. Those chapters are taken up chiefly with shanti, the propitiatory rites to be performed for the child, which they set out step by step.

The tithis also fall into five families that repeat three times in each half-month: Nanda (the first, sixth and eleventh), Bhadra (second, seventh, twelfth), Jaya (third, eighth, thirteenth), Rikta (fourth, ninth, fourteenth) and Purna (fifth, tenth, fifteenth), groups Muhurta Chintamani draws on in choosing times. The example's Shashthi is a Nanda tithi, and the birth sat many hours clear of the Panchami junction of the evening before.

Where a birth panchang needs care

Apart from the vara, which turns over once a day at sunrise, every limb can change at any hour, so the panchang is only as reliable as the time behind it. A boundary close to the recorded time — like the Kaulava–Taitila change just after the example birth — leaves that limb uncertain if the time was rounded. The unknown-time check has a blind spot of its own: on a date that contains a whole short tithi, the two ends of the day name the tithis either side of it, and the one in between was possible too.

Published panchangs also differ in method. Some work from the true, observed positions of the Sun and Moon (drik ganita), others from the older mean-motion rules of the siddhantas, and the two can put a tithi boundary minutes or even hours apart; this engine uses drik positions. Month names differ too: the amanta reckoning of the south and west ends each month at the new moon and the purnimanta reckoning of the north at the full moon, so they agree in Shukla paksha and are a month apart in Krishna paksha.

Can I find my birth tithi from my date of birth alone?

Not with certainty on most dates. A tithi lasts roughly a day but starts and ends at any hour, so nearly every calendar date holds the close of one tithi and the opening of another. With a birth time and place the calculator settles it. Without a time, the honest answer is a short list: the tithi current at midnight and the one current just before the next midnight.

How is the janma tithi used to celebrate a Hindu birthday?

Many families keep a lunar birthday on the day the janma tithi comes round again in the same lunar month as the birth, alongside or instead of the Gregorian one. Since twelve lunar months fall about eleven days short of a solar year, that celebration moves around the Gregorian calendar from year to year, and households follow their own custom when the tithi does not prevail at sunrise.

Why does the panchang give a different weekday for my birth?

Because the Vedic day begins at sunrise, not at midnight. If you were born after midnight but before that morning's sunrise, the civil calendar has already moved to the next day while the vara is still the previous one. The calculator shows both the civil weekday and the vara, measured against the actual sunrise time at your birthplace.

What is the difference between tithi and nakshatra?

A tithi measures the angle between the Moon and the Sun, in steps of 12°, so it follows the Moon's phase. A nakshatra measures the Moon's own place against the stars, in steps of 13°20′. They change at different moments, which is why a birth panchang lists both: the example birth was in Shukla Shashthi by tithi and in Dhanishta by nakshatra.

What are kshaya and vriddhi tithis?

They come from naming each civil day after the tithi current at sunrise. A tithi that starts after one sunrise and ends before the next is never current at a sunrise, so no day bears its name; that is kshaya. A tithi spanning two sunrises names two consecutive days; that is vriddhi, also called adhika. Neither changes the tithi of a birth, which is taken at the birth moment itself.

Does the birth tithi decide anything about a person?

On its own it records the Moon's phase at birth. Classical texts single out a few tithis and the junctions called gandanta, and prescribe propitiatory rites for births at those times. A reading weighs the tithi with the rest of the panchang and the whole chart, and this page presents it as a calculation, not a prediction.