When is Karva Chauth?

How the date is decided

Karva Chauth is Kartik Krishna Chaturthi — the fourth tithi of the waning fortnight of Kartik, counted in the purnimanta reckoning that names the month after the full moon that ends it.

What makes it unusual is the fourth condition. Every festival needs a rule for which civil day it lands on when its tithi spans two, and that rule names a moment of the day at which the tithi has to be prevailing. The classical term is vyapini. Most observances use sunrise. Ganesh Chaturthi uses midday, Diwali uses the hour after sunset, Shivratri uses midnight.

Karva Chauth uses moonrise, and it is the only major festival in this calendar that does. The reason is the rite: the fast ends when the Moon is sighted, so the day that matters is the day whose moonrise falls under Chaturthi. Judging it at sunrise instead would sometimes hand you a day whose Moon rises after the tithi has already gone.

Why this festival is more local than the others

For most festivals the national date and your local date are the same, because sunrise across India varies by under an hour and the tithi boundaries rarely land in that window. Karva Chauth is more exposed, for two compounding reasons.

Moonrise moves by roughly 50 minutes a day and its spread across a wide country is larger than sunrise’s. And the Chaturthi tithi is short. The result is that the same rule applied at Kolkata and at Ahmedabad is closer to disagreeing than it is for, say, Guru Purnima.

We publish one national date, computed at New Delhi, because that is the convention the almanacs use and the answer people expect. If you are fasting, the number you actually need is your own moonrise, and the panchang for your city gives it for any date.

Reading the day’s panchang

On the day itself, three lines are worth checking beyond the moonrise:

• the exact end of Chaturthi, so you know whether the tithi is still running when the Moon appears;
• Rahu Kaal, which many families avoid for the sankalp even though it has no bearing on the fast;
• the day’s choghadiya, if the puja is being timed rather than simply performed at moonrise.

Karva Chauth and Sankashti Chaturthi

Both fall on Krishna Chaturthi and both are judged at moonrise, so they look like the same rule. They are — Sankashti is the monthly form, observed on the Krishna Chaturthi of every lunar month, and Karva Chauth is the Kartik one carrying its own name and its own customs. When Karva Chauth fires, the monthly Sankashti Chaturthi is suppressed for that month so the day is not listed twice.

What we do not compute

We fix the day and give you moonrise for your city. We do not compute the regional sighting conventions, the sargi timings observed before dawn, or the puja muhurat inside the evening. Those vary by community in ways a calendar rule cannot settle honestly.