Parama Ekadashi is the second of the two Ekadashis of the Adhika masa, the extra month of the lunar calendar. It is the one of the dark half, and it comes about once every three years. The word parama means supreme or highest, and the extra month, called Purushottama, is regarded as the month of Vishnu, so its two Ekadashis are given particular honour.
Parama Ekadashi belongs to Adhika Jyeshtha, the extra month the lunar calendar adds about every third year to keep it in step with the seasons (see Adhika Masa). It is in the Krishna, the waning paksha. This site labels it Adhika Jyeshtha in both the amanta and the purnimanta reckoning, but regional purnimanta calendars do not all name the dark half of an extra month the same way, so check your own.
The katha
The tradition attributes the stories of the Ekadashis, Parama Ekadashi among them, to the Padma Purana and the Bhavishyottara Purana, where they are told as conversations, often with Krishna answering Yudhishthira. This story has no kings or demons, only a poor household.
In the city of Kampilya lived a Brahmin named Sumedha with his wife Pavitra. Sumedha was honest and learned, but they were very poor, and often had nothing to eat. Pavitra, who was devoted to her husband and to the guests who sometimes came, suggested that he go abroad to find work. Sumedha replied that wealth comes from what a person has done before and not from where he goes, and he would stay.
One day the sage Kaundinya came to their house. They received him with what little they had, and he, seeing their state, told them of the Parama Ekadashi of the extra month, and said that a five-day vow starting on it would bring them relief. The couple kept the vow with devotion.
The tradition says that on the last day a stranger arrived and gave them a house, along with the means to live comfortably, and that this was Kubera’s doing in some tellings, because Kubera is the god of wealth. The story is told to say that patience and faith make a house a better home, and the five-day vow is still followed by some families in the extra month.
How the fast is kept
The vow of the story is a five-day one, beginning with Ekadashi, and the practice varies from family to family. Many people simply keep the single day of Ekadashi and spend the extra month with a little more prayer, reading and giving.
Giving is the theme of the story: Sumedha and Pavitra shared what they had with a guest, and many people mark the day by giving food, grain or clothing to someone who has less.
In the tables, Parama Ekadashi is placed by the Smarta rule (Ekadashi at sunrise). If you keep Vaishnava practice you may be told to fast for Parama Ekadashi on the day after, because that tradition does not accept an Ekadashi that is touched by Dashami near dawn. The next morning the fast is broken in the parana window, between sunrise and the end of Dwadashi and not in Hari Vasara, the first quarter of Dwadashi. Whatever form Parama Ekadashi takes in your home, let it be a fast you can sustain. If you are expecting, nursing, ageing or managing an illness, a light meal of fruit and milk with prayer is enough, and your doctor should decide about medicines.
Where it sits in the year
Parama Ekadashi follows Padmini Ekadashi and comes just before Nirjala Ekadashi, which resumes the regular round of the year. Every Ekadashi of the year is listed on the Ekadashi page; the steps of worship for Parama Ekadashi are in the Ekadashi vrat vidhi, and the tithi itself is explained on the Ekadashi tithi page.