What is a tithi?
A tithi is a lunar day. At Amas (new moon) the Moon and the Sun are in the same direction. Each time the Moon moves another 12 degrees ahead of the Sun, one tithi ends. That gives 30 tithis in a month.
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Sud and Vad
Each month has two halves. After Amas the Moon grows: that is Sud (Shukla paksha). After Punam it shrinks: that is Vad (Krishna paksha). Each half has 15 tithis. The 15th of Sud is Punam (full moon) and the 15th of Vad is Amas (new moon).
| No. | Sud | Vad |
|---|---|---|
| 1 | Ekam | Ekam |
| 2 | Bij | Bij |
| 3 | Trij | Trij |
| 4 | Choth | Choth |
| 5 | Pancham | Pancham |
| 6 | Chhath | Chhath |
| 7 | Satam | Satam |
| 8 | Atham | Atham |
| 9 | Nom | Nom |
| 10 | Dasham | Dasham |
| 11 | Agiyaras | Agiyaras |
| 12 | Baras | Baras |
| 13 | Teras | Teras |
| 14 | Chaudas | Chaudas |
| 15 | Punam | Amas |
Which tithi counts for the day? (udaya tithi)
A tithi does not change with the clock; it can start or end at any time of day. In the Gujarati panchang, the tithi running at sunrise is the tithi for the whole day. This is called the udaya tithi. VedicSamay shows the day's tithi together with the time it ends.
How long is a tithi?
The Moon does not move at a steady speed, so a tithi can last from about 19 to 26 hours. That creates two special cases:
- Kshaya tithi: a tithi starts and ends between two sunrises, so no day is named after it.
- Vriddhi tithi: a tithi lasts across two sunrises, so two days in a row have the same tithi.
Gujarati months
Gujarat follows the Amanta system: each month ends on Amas. The Gujarati year starts with Kartak.
| Gujarati month | Sanskrit name | Roughly |
|---|---|---|
| Kartak | Kartika | October – November |
| Magshar | Margashirsha | November – December |
| Posh | Pausha | December – January |
| Maha | Magha | January – February |
| Fagan | Phalguna | February – March |
| Chaitra | Chaitra | March – April |
| Vaishakh | Vaishakha | April – May |
| Jeth | Jyeshtha | May – June |
| Ashadh | Ashadha | June – July |
| Shravan | Shravana | July – August |
| Bhadarvo | Bhadrapada | August – September |
| Aso | Ashvin | September – October |
North India follows the Purnimanta system, where a month ends on Punam. In the Vad half, their month name is one ahead of ours. For example, our Aso Vad is Kartik Krishna in North India. The festival date is the same; only the month name differs.
Adhik maas
A lunar year is about 11 days shorter than a solar year. To keep them together, an extra month is added roughly every three years, called Adhik maas. A month in which the Sun does not enter a new rashi becomes the Adhik month.
Vikram Samvat
The Gujarati new year starts the day after Diwali, on Kartak Sud Ekam (Besatu Varas). Vikram Samvat is 56 or 57 years ahead of the common era: the year + 56 until Diwali, and + 57 after.
How we calculate the tithi
We calculate the positions of the Moon and the Sun at your city's sunrise. The moment a tithi ends is the same worldwide, but each city sees it in local time. That is why a city abroad can sometimes have a different tithi from India on the same date.
Frequently asked questions
How do I know when Agiyaras (Ekadashi) is?
The 11th tithi of both Sud and Vad is Agiyaras (Ekadashi). Fast dates follow the udaya tithi; Vaishnav and Smarta traditions sometimes differ by a day.
Why is the tithi abroad different from India?
The tithi is taken at sunrise, and sunrise in London or New York comes hours after India. If the tithi changes in between, the local tithi is different.
Which tithis are Punam and Amas?
Punam is the 15th tithi of Sud and Amas is the 15th tithi of Vad.