Ekadashi is the 11th lunar day (Tithi), occurring twice a month when the Moon is at 120°–132° (Shukla) or 300°–312° (Krishna) elongation from the Sun. Revered as a principal fast in Vaishnava and Smartha practice, the fast must strictly conclude the next morning (Dwadashi) within a calculated time window called Parana, avoiding the first quarter of Dwadashi known as Harivasara.
☕ A Fortnightly Fast Timed by the Moon
Long before 'intermittent fasting' became a modern wellness phrase, the fortnightly Ekadashi fast was a fixed part of Indian religious life. It falls on the 11th tithi of each fortnight, about four days before the Full Moon (Pournami) and the New Moon (Amavasya).
Tradition links the fast to the Moon's approach to Full or New Moon and describes it as cleansing for body and mind. That is the custom's own rationale, not a measured effect of the Moon on the body. In practice, abstaining from grains and heavy food gives the digestive system a day of rest and leaves the day free for prayer and study.
However, an authentic Ekadashi fast is governed by a strict astronomical rulebook: breaking the fast (Parana) cannot happen at any random hour. It must occur within a precise mathematical window after sunrise on Dwadashi.
Myth vs. Reality: Ekadashi & Parana Timing Rules
- Fasting on fruits, warm water, milk, or pure water (Nirjala for healthy adults)
- Engaging in spiritual reading, Vishnu Sahasranama chanting, and silent meditation
- Consuming gooseberry (Amla), sundakkai, and agathi keerai during Dwadashi Parana, as tradition prescribes
- Breaking fast promptly within the designated Parana window after sunrise on Dwadashi
- Consuming rice, wheat, pulses, and heavy starchy grains on Ekadashi day
- Breaking fast during Harivasara (the first 25% of Dwadashi tithi) — considered to cancel fasting merit
- Fasting past midday on Dwadashi (fast must be broken before Dwadashi ends or before solar noon)
- Force-fasting elderly individuals, pregnant mothers, or patients on critical medical prescriptions
Frequently Asked Questions
Why is rice specifically prohibited on Ekadashi?
Traditional explanations hold that rice is heavy and water-retaining and dulls the focus the fast is meant to sharpen. Esoterically, the epic texts describe sinful proclivities taking refuge in grains on this day to encourage self-restraint.
What is Harivasara?
Harivasara is the first quarter (Pada 1) of Dwadashi tithi. The Ekadashi fast is not broken during Harivasara; one waits until it has passed and then breaks the fast in the morning.
What happens if Dwadashi ends before sunrise?
If Dwadashi tithi ends before sunrise the next morning, the fast is broken immediately after sunrise in the early morning hours, which tradition accepts as a permitted exception (Apaddharma).
What is the difference between Smartha and Vaishnava Ekadashi?
Smarthas fast on the day Ekadashi prevails at sunrise. Sri Vaishnavas are stricter: Dashami (the 10th tithi) must have ended before arunodaya, the 96 minutes before sunrise; if it touches that window the Ekadashi is 'viddha' and they fast the next day. Nava shows the two as separate observances, and on most days they coincide.
Deep Dives: Parana Window Calculation Mathematics
The Harivasara quarter, Dwadashi tithi fractions, and the morning rule for Parana.
📐 Harivasara Duration Formula
A Tithi spans exactly 12 degrees of solar-lunar angular separation. One quarter (Pada or Charana) spans 3 degrees of longitude.
1 Pada = 3° = 15 Ghatikas (nominal, ~6 hours)
Harivasara = First Pada (first ~15 Ghatikas) of Dwadashi
Parana can only begin once the Moon crosses the 3-degree mark of Dwadashi (after Harivasara ends).
⏱️ Dwadashi Morning Parana Window Logic
The canonical rule states: Pratah Kale tu Kartavyam Paranam (Parana should be done in the morning). If Dwadashi ends before noon, Parana must be completed before Dwadashi expires. If Dwadashi lasts through the day, Parana must be completed within the first one-third of daylight (Pratah Kala, roughly 4 hours on a 12-hour day).