Why Are There Two Tithis in One Day? Kshaya and Vriddhi Tithi Explained
Seen two tithis listed for the same date, or a tithi that seems to be missing? Here is why it happens, and how to decide which tithi to follow for your vrat.
Open any panchang and you will often see a line like "Tritiya till 01:07 AM, then Chaturthi". Some days even list a tithi that seems to start and finish while you sleep. This confuses many people planning a fast. The explanation is straightforward once you see how a tithi works.
Tithis don't follow the clock
A tithi is the time the Moon takes to move 12° ahead of the Sun. Because the Moon's speed changes through its orbit, a tithi can be as short as about 20 hours or as long as about 27 hours.
A civil day, from midnight to midnight, is always 24 hours. A Hindu day, from sunrise to the next sunrise, is close to 24 hours. Tithis of irregular length laid over days of regular length will almost never line up. So on most days, one tithi ends and the next begins somewhere in the middle.
That is the "two tithis in one day" you see in the panchang. It is completely normal. Roughly two days out of three contain a tithi change between sunrises.
Which tithi is the day's tithi?
The tithi running at sunrise (the udaya tithi) governs the day for most purposes. If Ekadashi prevails at sunrise and Dwadashi begins at 2 p.m., the day is counted as Ekadashi.
Our live tithi page shows a sunrise-to-sunrise bar so you can see exactly where the change happens.
Kshaya tithi: the "missing" tithi
Sometimes a short tithi begins after one sunrise and ends before the next. It never touches a sunrise, so it never becomes the udaya tithi of any day. In the calendar it seems to vanish. This is called a kshaya (decayed) tithi.
Example: if Dashami prevails at Monday's sunrise, Ekadashi begins at 8 a.m. Monday and ends at 5 a.m. Tuesday, then Dwadashi prevails at Tuesday's sunrise. Ekadashi has been skipped.
Festivals on a kshaya tithi are not cancelled. They move to the day on which the tithi actually occurs, following the rules for that festival. Our vrat pages mark such dates with a note.
Vriddhi tithi: the tithi that repeats
The opposite case is a long tithi that begins just before one sunrise and ends just after the next. It prevails at two consecutive sunrises, so the same tithi is counted for two days. This is a vriddhi (increased) tithi.
For festivals, the scriptures specify which of the two days to use, and the answer varies. For Ekadashi, Smarta tradition usually fasts on the first day while Vaishnava tradition, which avoids Ekadashi "touched" by Dashami, often fasts on the second. That is why calendars sometimes list two Ekadashi dates.
Why the date can differ between cities
Since the decision depends on sunrise, location matters. A tithi that ends at 6:20 a.m. in Delhi might end after sunrise in Kolkata (where the Sun rises earlier) but before sunrise in Mumbai (where it rises later). The two cities can therefore observe the same vrat on different dates. For the diaspora in the USA, UK or Australia, the difference is even larger.
This is why we calculate everything city by city.
How to use this in practice
- Find your city's panchang for the day.
- Note the tithi at sunrise and when it ends.
- For a vrat, check the observance rule. Our vrat pages apply sunrise, sunset, moonrise and midnight rules for you.
- When two dates are given, follow your family or sampradaya tradition.
For the stories and rituals of the major festivals themselves, see the festival guides on SpiritualMarg.
Summary
- Two tithis in one day is normal, because tithis are 20–27 hours long.
- The tithi at sunrise is the tithi of the day.
- A tithi that never touches a sunrise is kshaya; one that touches two is vriddhi.
- Sunrise varies by place, so the observance date can too.