Panchang · Glossary
Tithi
तिथि
A lunar day in the Hindu calendar — the time taken for the Moon to advance 12° from the Sun. There are 30 tithis in each lunar month.
Tithi is the fundamental unit of the Hindu lunar calendar. Unlike a solar day (which tracks the Sun's movement), a tithi tracks the angle between the Moon and the Sun. When the Moon moves exactly 12° ahead of the Sun, one tithi is complete. This means tithis can be longer or shorter than 24 hours, and sometimes a tithi can begin and end within the same solar day (making it 'lost' — Kshaya tithi) or extend across two solar days (Vriddhi tithi). There are 30 tithis in a lunar month: 15 in the Shukla Paksha (waxing, from new moon to full moon) and 15 in the Krishna Paksha (waning, from full moon to new moon). The tithis are named: Pratipada (1st), Dwitiya (2nd), Tritiya (3rd) … through Chaturdashi (14th), Purnima (15th/full moon), and back through the waning tithis to Amavasya (new moon). Hindu festivals and rituals are timed by tithi, not calendar date — which is why their Gregorian dates shift each year.
Examples
- ◆Diwali falls on Kartik Amavasya (new moon of the month of Kartik) — the tithi, not the date, determines Diwali
- ◆Ganesh Chaturthi falls on Bhadra Shukla Chaturthi (4th tithi of the waxing fortnight of Bhadra month)
- ◆Ekadashi (11th tithi) is the most widely observed fasting tithi — once in each fortnight, twice a month
Related Terms
Frequently Asked Questions
What is tithi in Hindu calendar?
Tithi is a lunar day in the Hindu calendar — the time the Moon takes to move 12 degrees ahead of the Sun. There are 30 tithis in a lunar month: 15 in the waxing (Shukla) fortnight and 15 in the waning (Krishna) fortnight. Hindu festivals are timed by tithi rather than calendar date, which is why their dates in the Gregorian calendar shift each year.
How is tithi different from a solar day?
A solar day is exactly 24 hours — the time the Earth takes to rotate. A tithi is the time the Moon moves 12° relative to the Sun, which varies from about 19 to 26 hours due to the Moon's elliptical orbit. Sometimes a tithi can be skipped (Kshaya tithi) or repeat (Vriddhi tithi) in the Gregorian calendar, which is why panchang consultation is needed for exact festival timings.
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