What is Tithi?
A Tithi is a lunar day — the time it takes for the angular distance between the Moon and the Sun to increase by 12 degrees. Because the Moon's speed varies, a tithi can last anywhere from about 19 to 26 hours, which is why tithis don't line up neatly with calendar days and why a panchang shows the exact end time.
There are 30 tithis in a lunar month, split into two halves (Paksha): the 15 tithis of the waxing Moon are "Shukla Paksha" (bright fortnight), and the 15 tithis of the waning Moon are "Krishna Paksha" (dark fortnight).
Tithis are used to decide the dates of festivals, vrat (fasts), and auspicious muhurats — which is why most Hindu festival dates shift every year on the standard calendar.
Frequently Asked Questions
What is a Tithi in the Hindu calendar?
A Tithi is a lunar day — the time it takes for the angular distance between the Moon and the Sun to increase by 12 degrees. There are 30 tithis in a lunar month.
How long does one Tithi last?
A tithi can last anywhere from about 19 to 26 hours, because the Moon's speed along its orbit varies. This is why tithis don't line up neatly with calendar days.
What is the difference between Shukla Paksha and Krishna Paksha?
Shukla Paksha (bright fortnight) is the 15 tithis of the waxing Moon, ending at the full moon (Purnima). Krishna Paksha (dark fortnight) is the 15 tithis of the waning Moon, ending at the new moon (Amavasya).
Why does Tithi matter for festivals and muhurat?
Tithis are used to decide the dates of festivals, vrat (fasts) and auspicious muhurats — which is why most Hindu festival dates shift every year on the standard Gregorian calendar.