What is Tithi? (திதி)
The Lunar Day in Hindu Panchangam — Explained
Definition of Tithi
A Tithi (திதி) is the fundamental unit of time in the Hindu lunar calendar. It is defined as the period during which the Moon travels 12° ahead of the Sun along the ecliptic. Since the Sun also moves during this period, a Tithi represents a 12° increase in the angular separation between Moon and Sun.
A full lunar month consists of 30 Tithis: 15 during the waxing phase (Shukla Paksha, lit. "bright fortnight") from New Moon to Full Moon, and 15 during the waning phase (Krishna Paksha, lit. "dark fortnight") from Full Moon back to New Moon.
Because the Moon's orbital speed varies (it moves faster near perigee and slower near apogee), the duration of a Tithi can range from about 19 to 26 hours. This means a Tithi can skip an entire solar day or span parts of three solar days.
The Five Tithi Groups
The 30 Tithis are classified into five groups based on their astrological quality. This grouping repeats six times through the lunar month (positions 1–5, 6–10, 11–15 in both Pakshas):
All 30 Tithis
| # | Paksha | Sanskrit Name | Tamil Name | Group |
|---|---|---|---|---|
| 1 | ☽ Shukla | Prathama | பிரதமை | Nanda |
| 2 | ☽ Shukla | Dvitiya | துவிதியை | Bhadra |
| 3 | ☽ Shukla | Tritiya | திருதியை | Jaya |
| 4 | ☽ Shukla | Chaturthi | சதுர்த்தி | Rikta |
| 5 | ☽ Shukla | Panchami | பஞ்சமி | Purna |
| 6 | ☽ Shukla | Shashthi | சஷ்டி | Nanda |
| 7 | ☽ Shukla | Saptami | சப்தமி | Bhadra |
| 8 | ☽ Shukla | Ashtami | அஷ்டமி | Jaya |
| 9 | ☽ Shukla | Navami | நவமி | Rikta |
| 10 | ☽ Shukla | Dashami | தசமி | Purna |
| 11 | ☽ Shukla | Ekadashi | ஏகாதசி | Nanda |
| 12 | ☽ Shukla | Dvadashi | துவாதசி | Bhadra |
| 13 | ☽ Shukla | Trayodashi | திரயோதசி | Jaya |
| 14 | ☽ Shukla | Chaturdashi | சதுர்தசி | Rikta |
| 15 | ☽ Shukla | Pournami | பௌர்ணமி | Purna |
| 16 | 🌑 Krishna | Prathama | பிரதமை | Nanda |
| 17 | 🌑 Krishna | Dvitiya | துவிதியை | Bhadra |
| 18 | 🌑 Krishna | Tritiya | திருதியை | Jaya |
| 19 | 🌑 Krishna | Chaturthi | சதுர்த்தி | Rikta |
| 20 | 🌑 Krishna | Panchami | பஞ்சமி | Purna |
| 21 | 🌑 Krishna | Shashthi | சஷ்டி | Nanda |
| 22 | 🌑 Krishna | Saptami | சப்தமி | Bhadra |
| 23 | 🌑 Krishna | Ashtami | அஷ்டமி | Jaya |
| 24 | 🌑 Krishna | Navami | நவமி | Rikta |
| 25 | 🌑 Krishna | Dashami | தசமி | Purna |
| 26 | 🌑 Krishna | Ekadashi | ஏகாதசி | Nanda |
| 27 | 🌑 Krishna | Dvadashi | துவாதசி | Bhadra |
| 28 | 🌑 Krishna | Trayodashi | திரயோதசி | Jaya |
| 29 | 🌑 Krishna | Chaturdashi | சதுர்தசி | Rikta |
| 30 | 🌑 Krishna | Amavasai | அமாவாசை | Purna |
Frequently Asked Questions
What is a Tithi in Panchangam?
Tithi is the lunar day in the Hindu calendar. It is calculated as the angular distance between the Sun and Moon divided into 30 segments of 12° each. Unlike a solar day (24 hours), a Tithi can be shorter or longer than a solar day.
How many Tithis are there?
There are 30 Tithis in a lunar month — 15 during the waxing fortnight (Shukla Paksha) and 15 during the waning fortnight (Krishna Paksha). The 15th Tithi of Shukla Paksha is Pournami (Full Moon) and the 30th (or 15th of Krishna Paksha) is Amavasai (New Moon).
What are the five Tithi groups?
The 30 Tithis are grouped into five categories based on their qualities: Nanda (1, 6, 11 — joyful), Bhadra (2, 7, 12 — auspicious), Jaya (3, 8, 13 — victorious), Rikta (4, 9, 14 — empty/inauspicious), and Purna (5, 10, 15 — complete/full).
Can two Tithis fall on the same calendar day?
Yes. Since Tithis can be shorter than 24 hours, two Tithis can sometimes both begin and end on the same solar day. Conversely, a Tithi can span more than 24 hours and cover parts of three calendar days.