Indian lunar calendar


Each month consists of 29 to 30 days, and is based on the phases of the moon. Each month is divided into two fortnights (paksha). Shukla Paksha (Sudi) ends with a Purnima (full moon), and Krsna Paksha (Vaadi) ends with a Amavasya (New Moon). In some regions, (e.g.., Uttar Pradesh) the month starts with Krsna Paksha following Purnima, but for most regions of Bharat (India), the month starts with Shukla Paksha following Amavasya. This calendar is mentioned in Anuwalk 6, Sookta 25 and mantra 8 of Rigvedah Sanhita. And thus has been in practice for at least 6000 years before Buddha. The mantra also mentions Adhika Maas described below. Further indian astronomy is based on 9 planets and sun including moon, even though the calendar is based on moon. Even though the months are same some most Indians start Indian new year with Holi and some with Deepawali.

The twelve months of the lunar year correspond to the following calendar months and make up the six seasons (Rutu) ( Thses 6 ritus are mentioned in Anuwalk 1, Sookta 23 and mantra 10 of Rigveda Sanhita ) :


1.Chaitra (March-April)

2.Vaishakh (April-May) ............... Vasanta Rutu (Spring)

3.Jyeshta (May-June)

4.Aashaadh (June-July) ............... Greeshma (Summer)

5.Sharaavan (July-August)

6.Bhadrapad (August-September) ......... Varsha (Monsoon)

7.Ashwin (September-October)

8.Kaartik (October-November) ......... Sharad (Autumn)

9.Margasheersh (November-December)

10.Paush (December-January) ......... Hemanta (Winter)

11.Maagh (January-February)

12.Phalgun (February-March) ........... Shishira (Dewey)


Adhika (Purushottam) Maas

Since the calendar is based on the phases of the moon, the twelve as above take 354 days, 8 hours and 34.28 seconds. This creates a difference of 10 days, 21 hours and 35.16 seconds from the actual solar year (365 days, 6 hours, 9.54 seconds).


When the accumulated difference exceeds 29 days, 12 hours, 44 minutes and 2.865 seconds, an adjustment id made with a extra month (Adhika Maas), which carries the name of the previous or the next month, depending on the proximity of the month. Normally, seven extra months occur in 19 years.


Shalivahan Shaka

The Shalivahan Shaka is based on the lunar calendar and the new year starts with Chaitra Maas (Shukla Paksha). The current year (1914) started on April 2, 1992. This calendar is believed to have been initiated by King Shalivahan in the year 78 A.D.


Vikram Samvat

The Vikram Era started with Raja Vikramaditya of Ujjain, following his victory over the Saka in 56 B.C. The new year begins with the first day of Kartik following Deepawali Amavasya. The current Vikram Samvat is 2048. The Yudhisthir Shaka, which started approximately around 5500 B.C, is not very popular today.