Sankashti Chaturthi is a monthly vrat dedicated to Ganesha, observed on the Chaturthi (fourth tithi) of Krishna paksha, the waning fortnight after Purnima. The name suggests relief from difficulties, and many families keep it every month as a steady devotional practice.

How the date is decided

Unlike most vrats, Sankashti is tied to the Moon's rising. The vrat is kept on the day when Krishna Chaturthi prevails at moonrise. The day's fast usually begins in the morning and is completed after moonrise, once the Moon has been sighted and offered arghya (water), followed by Ganesha puja.

Since the Moon rises later each evening during the waning fortnight, the Chaturthi Moon generally appears a few hours after sunset. It is therefore quite possible for Chaturthi to be the sunrise tithi on one day but for the vrat to fall on another, depending on which evening's moonrise it covers. In the uncommon case that Chaturthi covers no moonrise at all, this platform falls back to the day on which Chaturthi prevails the longest.

Angaraki Chaturthi

When Sankashti falls on a Tuesday (Mangalvar, the day of Angaraka or Mars), it is called Angaraki Chaturthi and is traditionally regarded as especially auspicious. Some Krishna Chaturthis also carry their own names; for example, Karva Chauth, kept in North India on Kartika Krishna Chaturthi (Purnimanta), follows the same moonrise rule.

Why moonrise time differs by city

Moonrise depends strongly on the observer's location. On this platform, moonrise is defined as the moment the centre of the Moon reaches the horizon as seen from your location (topocentric), without adding atmospheric refraction. Because the Moon is close to the Earth, its apparent position shifts noticeably with place, so moonrise can differ by many minutes between cities, and occasionally the vrat date itself can differ. Other almanacs that use the upper edge of the Moon or include refraction may print slightly different times.

Sankashti and Vinayaka Chaturthi

The two monthly Ganesha observances are easy to confuse:

  • Sankashti Chaturthi: Krishna paksha Chaturthi, decided by moonrise; fast completed after seeing the Moon.
  • Vinayaka Chaturthi: Shukla paksha Chaturthi, decided by Madhyahna (the midday part of the day), when Ganesha puja is performed.

Traditions may vary by region and Panchang convention. See upcoming dates and local moonrise times on the Sankashti Chaturthi page, or read more about Tithi.