Panchang guide / Ekadashi, amavasya, purnima
Ekadashi, amavasya and purnima: why the dates differ
Ekadashi, Amavasya and Purnima are the tithis most people track, for fasts, offerings and festivals. Their dates sometimes differ between calendars by a day. Here is why.
Purnima: full moon
Purnima is the 15th tithi of the bright half, when the Moon is opposite the Sun. Many festivals fall on it: Guru Purnima, Raksha Bandhan, Sharad Purnima, Kartik Purnima and Holi (Holika Dahan). Purnima fasts are kept on the day Purnima prevails, often judged at moonrise or in the evening.
Amavasya: new moon
Amavasya is the last tithi of the dark half, when the Moon and Sun are together and the Moon is invisible. It is the traditional day for offerings to ancestors (pitru tarpan), and Diwali’s Lakshmi Puja falls on the Amavasya of Kartika (purnimanta) or Ashvin (amanta). Mahalaya and Mauni Amavasya are among the best known.
Ekadashi: the eleventh day
Ekadashi is the 11th tithi of each half, so there are 24 in a normal year and 26 in a year with an adhik maas. Each has its own name, such as Nirjala, Devshayani and Prabodhini Ekadashi. It is kept as a fast, broken the next day (parana) within a set window on Dwadashi.
Ekadashi has a stricter rule than other tithis. Vaishnava calendars require that the previous tithi, Dashami, has ended before arunodaya, the dawn period about 1 hour 36 minutes before sunrise. If Dashami is still running then, the fast moves to the next day. Smarta calendars usually follow the ordinary sunrise rule. That is the most common reason two calendars show Ekadashi on different days.
Why dates differ between cities
A tithi begins and ends at the same instant everywhere, but each calendar date is judged at local sunrise. Suppose Amavasya ends at 8:00 am India time. In Delhi it is still running at sunrise, so that day is Amavasya. In London, 8:00 am in India is 2:30 am in winter, before sunrise, so London’s day already belongs to the next tithi. Overseas families who follow an Indian-printed calendar can be a day out.
Check for your city: Today’s panchang shows the tithi and when it ends; the 2027 festival calendar gives festival dates for your location.