What is a tithi?
A tithi is a lunar day in the Hindu calendar. Each tithi is the time the Moon takes to gain 12 degrees on the Sun. Because the Moon's speed varies, a tithi can last anywhere from about 19 to 26 hours.
Tithi number = (Moon longitude − Sun longitude) ÷ 12°, rounded up
A lunar month has 30 tithis in two halves:
- Shukla Paksha (bright half): Pratipada to Chaturdashi, ending with Purnima (full moon).
- Krishna Paksha (dark half): Pratipada to Chaturdashi, ending with Amavasya (new moon).
The 15 tithis
| No. | Tithi | No. | Tithi |
|---|
| 1 | Pratipada | 9 | Navami |
| 2 | Dwitiya | 10 | Dashami |
| 3 | Tritiya | 11 | Ekadashi |
| 4 | Chaturthi | 12 | Dwadashi |
| 5 | Panchami | 13 | Trayodashi |
| 6 | Shashthi | 14 | Chaturdashi |
| 7 | Saptami | 15 | Purnima / Amavasya |
| 8 | Ashtami | | |
How we calculate it
We compute the exact positions of the Sun and Moon with a high-precision astronomy library, then find the tithi at sunrise in your city, which is the traditional rule for the day's tithi. End times are found by searching for the moment the Moon–Sun angle reaches the next 12° step, so they are accurate to about a minute.
Want the full day's details, including nakshatra, yoga, karana, Rahu Kaal and Abhijit Muhurat? Open the daily panchang.
Frequently asked questions
What is a tithi?
A tithi is a lunar day. It is the time the Moon takes to move 12 degrees ahead of the Sun. There are 30 tithis in a lunar month: 15 in Shukla Paksha (waxing Moon, ending with Purnima) and 15 in Krishna Paksha (waning Moon, ending with Amavasya).
Why does the tithi change in the middle of the day?
A tithi lasts between about 19 and 26 hours, so it rarely starts at sunrise. By tradition, the tithi running at sunrise is the tithi of the whole day. This page shows that tithi and the exact time it ends.
Why is the tithi different for different cities?
The tithi itself changes at the same moment everywhere, but sunrise times differ. Since the day's tithi is the one at local sunrise, two cities can occasionally have different tithis on the same date.
What is Purnimanta and Amanta month?
In the Amanta system (used in Gujarat, Maharashtra and South India) a month ends on Amavasya. In the Purnimanta system (used in most of North India) it ends on Purnima. They give the same name during Shukla Paksha and differ by one month during Krishna Paksha.
Are the Ekadashi dates exact for fasting?
They follow the sunrise rule for your city. Some traditions (Smarta and Vaishnava) use extra rules, so a vrat can occasionally be kept a day later. Check with your family priest or temple calendar for important vrats.