Article: Jain calendar

Contributed by Nalini Balbir

Lunar month

There are 12 lunar months in a year of the lunar calendar. A lunar month is the interval between two new moons or two full moons and lasts around 28 days. A Western month is based on the solar calendar so each Indian month begins about halfway through a Western month. The names of Indian months are derived from the names of the constellation – nakṣatra – where the corresponding full moon is at that time. For instance, in Caitra the full moon is in the constellation Citrā, in Vaiśākha the full moon is in the constellation Viśākha and so on.

Indian lunar calendar and Western equivalent

Sanskrit names

Gujarati names

English equivalent



March to April



April to May



May to June



June to July



July to August



August to September



September to October



October to November



November to December



December to January



January to February



February to March

The Gujarati names of the months are in widespread use in contemporary India and are clearly corruptions of the original Sanskrit terms.

In India the start of the year differs according to three factors. The first one is the era used, the second is the region of India and the last is the sphere of activity, which more or less means daily life versus religious life.

Indian era, regions of usage and year start



First month of the year


north India



south India





Jain era and Jain religious year


Kārttika with Dīvālī



Kārttika with Dīvālī

Lunar fortnight

This painting from a manuscript depicts the sun and moon. The deer is associated with the moon in Indian culture and is often used to symbolise the moon in pictures.

Sun and moon
Image by British Library © CC0 1.0 (Creative Commons Public Domain)

Each lunar month is divided into two fortnights – pakṣa in Sanskrit – the 'dark' fortnight and the 'bright' fortnight.

The dark fortnight or 'dark half' runs from the full moon to the new moon. It is known by an assortment of names, such as kṛṣṇa-pakṣa, asita-pakṣa or any other adjective meaning 'black' or 'dark' followed by the word pakṣa. In the abbreviated form often used in manuscript colophons, calendars and so on, it is given as vadi or vada.

The bright fortnight or 'bright half' runs from the new moon to the full moon. It is known as śukla-pakṣa or any other adjective meaning 'white' or 'bright' plus pakṣa. In the abbreviated form often used in manuscript colophons, calendars and so on, it is usually sudi or suda.

The beginning of the month depends on the region. In the north Indian calendar a month starts with the dark half of the month and ends with the bright half. But Gujaratis follow the south India system, where the month starts with the bright half and ends with the new moon or dark half (see Cort 2001: 179 and 180 with a table).

In the religious calendar, the time of a change in the phase of the moon is crucial and often corresponds to a specific ritual or holy day.

Lunar day

In daily life the basic date unit is the civil day, that is, a day running from sunrise to the next sunrise, also called a solar day.

A lunar day – tithi – is 1/30th of a lunar month and is calculated by the time it takes for the moon to increase its longitudinal angle from the sun by 12 degrees. A lunar day varies from around 19 to 26 hours in length, in contrast to the solar day of 24 hours. Therefore lunar days begin at different times in the solar day, and so the solar and lunar days rarely coincide.

In matters of religious life and the religious calendar, the tithi is the only relevant unit. In dating found in manuscripts or inscriptions, the words used to refer to the day are tithi but also dina and divasa. Occasionally the Arabic loan-word tārīkha, which is common in modern Indo-Aryan languages, is found in late Gujarati works or manuscripts. The Sanskrit term karmavāṭī can also be found in inscriptions and manuscript colophons, such as this example in the British Library. However, it is a rare term recorded in the 12th-century Abhidhānacintāṃaṇi, a thesaurus by the Jain monk and great author Hemacandra. It seems to be a remnant of a specific terminology the Jains devised to refer to 'civil' notions of time. Other surviving terms are karma-saṃvatsara for 'civil year' and karma-māsa for 'civil month' (see Balbir 2011).

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