Chaturmas Dates for Any Year, with the Parva Days Inside

This tool gives the Chaturmas dates for any year from 1900 to 2074 and for your own city: the Chaumasi Chaudas that open and close the retreat, Ashadha Purnima and Kartika Purnima, the Digambara reckoning beside the Shvetambara one, every parva day inside the four months, and the festivals that fall in them. Chaturmas (chaumasa) is the four-month retreat of the rains, when Jain ascetics stop walking from place to place and stay in one town. Our Chaumasa page explains why.

For Ahmedabad in 2026 the tool gives Ashadha Purnima on Wednesday 29 July and Kartika Purnima on Tuesday 24 November, with the three Chaumasi Chaudas of the year on 2 March, 28 July and 23 November, the dates our Chaumasa page prints.

How it works

The boundaries. Our Chaumasa page, following the Shvetambara Kalpasutra, gives the retreat as Ashadha Purnima to Kartika Purnima, and reports Ashadha Shukla 14 to Kartika Shukla 14 as the reckoning commonly given in Digambara sources. The four-monthly pratikraman, Chaumasi Chaudas, falls on the Shukla 14 of Phalguna, Ashadha and Kartika; the Ashadha one opens the retreat and the Kartika one closes it.

The civil days. For each day from June to December the tool reads the tithi at your city’s sunrise and names the lunar month the amanta way, from the Sun’s sidereal sign at the new moon that began it, with the same functions as our Paryushan and Samvatsari tool. A tithi at two sunrises is kept on the second day by Shvetambara sanghs and on the first by Digambara sanghs; a tithi at no sunrise is kept on the day before. The Digambara column uses the first day.

The observances inside. Paryushan, Samvatsari, Das Lakshana and Kshamavani come from the Paryushan tool’s own rules, the Ashvina Oli from our Ayambil Oli tool, and Diwali and the Jain new year from the rules on our Diwali and Vira Nirvana page: Diwali on the evening Kartika Amavasya is current at sunset, Digambara Deepavali on the morning it is at sunrise, and the new year at the first sunrise of Kartika Shukla. Gyan Panchami is Kartika Shukla 5. In some years Kartika Amavasya is current at two sunsets, and then the tool gives the first evening, as our Jain Panchang marks it, and says so. In others it begins after one sunset and ends before the next, so it is current at no sunset and the evening rule names no day: the tool then gives the times the Amavasya begins and ends and leaves the day to your sangh’s calendar.

Checked. For eight test places from Lautoka to New York, every boundary day, the observances inside, Diwali, the new year and Gyan Panchami were compared with an independent calculation made with the Swiss Ephemeris for each year from 1900 to 2074 at four places and from 2000 to 2035 at the other four. Of the 16,862 days compared, 16,845 agreed. Diwali was compared as every evening on which Kartika Amavasya is current at sunset: of the 844 place-years, 764 have one such evening, 27 have two and 53 have none, and the tool named the same evenings as the independent calculation in all 844. Each of the 17 differences is a day on which the tithi changes within about a minute of sunrise (1.2 minutes at most), where two careful calculations can fall on either side.

Reading the result

The first line gives the Shvetambara span and the two Chaumasi Chaudas. The table of boundary days adds the Phalguna Chaudas, the Digambara span and a note wherever a tithi was doubled or skipped. The observances table lists the festivals in date order, and the parva days open one month at a time, with the parva kept by Shvetambara sanghs and the Digambara parva (Ashtami and Chaturdashi) side by side.

Where traditions differ

• The boundaries. Shvetambara practice takes the retreat from Ashadha Purnima to Kartika Purnima; Digambara sources commonly give Ashadha Shukla 14 to Kartika Shukla 14. Many sanghs mark the start and the end with the Chaumasi Chaudas pratikraman.
• A doubled or skipped tithi. Shvetambara and Digambara sanghs keep a doubled tithi on different days, and gacchas differ on a doubled Punam or Amas, so a boundary can move by a day between calendars.
• An extra month. In a year with an adhika month inside the retreat, the span covers five lunar months instead of four, and the tool says so.
• Diwali in an unusual year. The evening rule names one evening in most years. When Kartika Amavasya is current at two sunsets the tool gives the first, as our Jain Panchang does; when it is current at none, the tool names no day. Sanghs can differ in such a year, so take Diwali from your sangh’s calendar.

Take the dates your own sangh announces. The tool gives the astronomical days by the sunrise rule so you can plan.

What it does not do

It does not tell you which niyams to take; the Chaumasa page describes the common ones. It does not say where any ascetic will keep the retreat, or when a tirth closes or reopens; Shatrunjaya at Palitana closes for the four months and its reopening is announced by the trust. For the pachkhan times of any day, use the pachkhan time calculator.

Frequently asked questions