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Glossary

Tithi defined: the lunar day measured by every 12 degrees the Moon gains on the Sun, its 30 steps across the two pakshas, what BPHS and Saravali say about it, and how this app computes and uses it.

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In short

A tithi is a lunar day: the time the Moon takes to gain 12 degrees on the Sun. Thirty tithis make one lunar month, numbered 1 to 15 in the bright half and 16 to 30 in the dark half. This app computes the tithi from the sidereal Sun and Moon, reads it at sunrise for the Panchang, and uses it in birth panchangs and muhurat scoring.

What the term means

A tithi is a lunar day, measured by angle, not by the clock. Each time the Moon pulls another 12 degrees ahead of the Sun, a new tithi begins. The thirty tithis are counted through the Shukla Paksha (1 to 15, waxing) and the Krishna Paksha (16 to 30, waning). The engine's own note puts a tithi at about 0.95 of a day, so it does not line up with a calendar day and can change at any hour, often inside a birth date.

Where the term comes from

Jyotisha Siddhanta Sara (Ch. II, pp. 26-27) gives the arithmetic the engine uses: thirty tithis of 12° each, the first starting at the conjunction of Sun and Moon, with the full Moon day 15th and the new Moon day 30th. Its worked example divides a separation of 337°20' by 12 and lands early in the 29th tithi, Krishna Chaturdashi. The older texts treat the tithi as working vocabulary. BPHS Ch. 78 Sl. 3-4 counts it among the birth details a query chart can recover. Ch. 85 Sl. 1-4 lists births on Amavasya, on Chaturdasi (the 14th tithi) and in Tithikshaya among inauspicious births. Ch. 92 Sl. 2 defines a Tithi Gandanta at the junction of a Purna tithi (5th, 10th, 15th) and a Nanda tithi (1st, 6th, 11th). Saravali Ch. 7 Sl. 4 ends each month with "the 30th Tithi (Amavasya)".

How this app computes it

  • Elongation is the sidereal Moon minus the sidereal Sun, from 0 to 360 degrees. Tithi = elongation divided by 12, rounded down, plus 1.
  • The Panchang calculator reads the tithi at local sunrise, as a printed panchang does; the Moon phase calculator reads it at a birth moment and says if it changed during the birth day.
  • The birth panchang names the tithi's group within its paksha: Nanda, Bhadra, Jaya, Rikta or Purna, a convention the engine attributes to Muhurta Chintamani.
  • In muhurat scoring, tithis 4, 8, 9, 14, 19, 23, 24 and 29 lose points; the engine notes that this list cites no text and that Amavasya is not on it.

A small illustration

At the birth moment of 19 January 1985, 11:14 IST, the engine gives an elongation of 337.2 degrees: 337.2 divided by 12 is 28.1, so the tithi is 29, the 14th of the Krishna Paksha, a Rikta tithi, with the Moon 3.9 per cent lit. On the morning of 13 October 2026 in New Delhi, the sunrise tithi is 3, in the Shukla Paksha.

Pages that use this term

Related terms

Paksha, Amavasya, Purnima, Panchang and Gandanta.

Now on yourself

Moon Phase and Tithi

The tithi, the paksha and how much of the Moon was lit on your birth date.

A birth time is optional. Without one this is read at local noon on your birth date - and the Moon moves about 13 degrees in a day, so add the time if you know it.

No place is asked for on this page, so the time is read as Indian Standard Time (IST). Born outside India? Run it on its own page, where you can add the place.

This date is sent only to compute the answer. Nothing is stored, no account is created, and no email is asked for.

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