In Vedic astrology, a tithi is not a fixed 24-hour period. It is a dynamic unit of lunar time: the Moon advances 12° relative to the Sun to complete one tithi. Because the Moon's speed varies, a tithi can last anywhere from about 19 to 26 hours. This is exactly how the Rasi & Rise engine computes the tithi for any given moment — by measuring the precise Sun–Moon elongation in degrees.
A lunar month contains 30 tithis, divided equally between the waxing (Shukla Paksha) and waning (Krishna Paksha) fortnights. The Shukla fortnight begins at Amavasai (new moon) and builds toward Pournami (full moon); the Krishna fortnight counts back down to the next new moon.
All 30 Tithis
Rows highlighted in red are avoided by the muhurtham engine for auspicious event scheduling.
| # | Name | Tamil | Note |
|---|---|---|---|
| 1 | Shukla Pratipada | சுக்ல பிரதமை | Generally favorable |
| 2 | Shukla Dwitiya | சுக்ல துவிதியை | Generally favorable |
| 3 | Shukla Tritiya | சுக்ல திருதியை | Generally favorable |
| 4 | Shukla Chaturthi | சுக்ல சதுர்த்தி | Generally favorable |
| 5 | Shukla Panchami | சுக்ல பஞ்சமி | Generally favorable |
| 6 | Shukla Shashthi avoid | சுக்ல சஷ்டி | Shashthi (6th lunar day) is linked to conflict and is avoided for new beginnings |
| 7 | Shukla Saptami | சுக்ல சப்தமி | Generally favorable |
| 8 | Shukla Ashtami avoid | சுக்ல அஷ்டமி | Ashtami (8th lunar day) is considered unstable and avoided for new beginnings |
| 9 | Shukla Navami avoid | சுக்ல நவமி | Navami (9th lunar day) carries aggressive energy and is avoided for auspicious events |
| 10 | Shukla Dashami | சுக்ல தசமி | Generally favorable |
| 11 | Shukla Ekadashi | சுக்ல ஏகாதசி | Generally favorable |
| 12 | Shukla Dwadashi | சுக்ல துவாதசி | Generally favorable |
| 13 | Shukla Trayodashi | சுக்ல திரயோதசி | Generally favorable |
| 14 | Shukla Chaturdashi avoid | சுக்ல சதுர்த்தசி | Chaturdashi (14th lunar day) is too close to the new/full moon and considered inauspicious |
| 15 | Pournami | பௌர்ணமி | Full moon — generally auspicious |
| 16 | Krishna Pratipada | கிருஷ்ண பிரதமை | Generally favorable |
| 17 | Krishna Dwitiya | கிருஷ்ண துவிதியை | Generally favorable |
| 18 | Krishna Tritiya | கிருஷ்ண திருதியை | Generally favorable |
| 19 | Krishna Chaturthi | கிருஷ்ண சதுர்த்தி | Generally favorable |
| 20 | Krishna Panchami | கிருஷ்ண பஞ்சமி | Generally favorable |
| 21 | Krishna Shashthi avoid | கிருஷ்ண சஷ்டி | Krishna Shashthi (6th lunar day, waning) is linked to conflict and avoided |
| 22 | Krishna Saptami | கிருஷ்ண சப்தமி | Generally favorable |
| 23 | Krishna Ashtami avoid | கிருஷ்ண அஷ்டமி | Krishna Ashtami (8th lunar day, waning) is considered unstable and avoided |
| 24 | Krishna Navami avoid | கிருஷ்ண நவமி | Krishna Navami (9th lunar day, waning) carries aggressive energy and is avoided |
| 25 | Krishna Dashami | கிருஷ்ண தசமி | Generally favorable |
| 26 | Krishna Ekadashi | கிருஷ்ண ஏகாதசி | Generally favorable |
| 27 | Krishna Dwadashi | கிருஷ்ண துவாதசி | Generally favorable |
| 28 | Krishna Trayodashi | கிருஷ்ண திரயோதசி | Generally favorable |
| 29 | Krishna Chaturdashi avoid | கிருஷ்ண சதுர்த்தசி | Chaturdashi (14th lunar day, waning) is too close to the new moon and considered inauspicious |
| 30 | Amavasai avoid | அமாவாசை | Amavasai (new moon) lacks lunar light and is avoided for auspicious activities |
How Tithis Affect Muhurtham Selection
The Rasi & Rise date finder uses a multi-factor scoring system. Tithi is one of its primary inputs. When a candidate date falls on one of the avoided tithis listed above, the engine applies a penalty to that date's score, reducing its likelihood of appearing among the top-ranked windows. This mirrors the classical panchangam approach, where the Shubha (auspicious) tithi is confirmed alongside nakshatra, yogam, and karanam before declaring a day suitable for muhurtham.
The tithi active at the start of your chosen event window is what matters — because the tithi boundary shifts continuously, two time slots on the same calendar day can fall under different tithis. The engine accounts for this by computing the exact Sun–Moon elongation at each candidate window's start time.
The strongest muhurtham dates combine a favorable tithi with a good nakshatra, an acceptable yogam, and an auspicious karanam. See our guides on yogams, karanams, and the glossary to understand each element.