By the middle of the 20th century, more than 30 calendars were used in India's various regions. The calculator below displays a given date converted to some Indian calendars.
To put an end to this mess, the Indian government commissioned scientists to develop a unified Indian calendar.
In 1955 the Indian Calendar Reform Committee completed the new National Indian Calendar. Its usage started officially on March, 22th 1957.
The following calculators convert a Gregorian date to the National Indian calendar date and vice versa.
However, the people of India did not accept the new calendar widely. The solar and lunisolar astronomical or true (spasta) calendars are in use actively at the moment. You can find below the solar and lunisolar Hindu calendar converters.
Each solar month begins when the Sun enters a new sign of the zodiac, the 30-degree sector of sidereal longitude. The sidereal longitudes are relative to the fixed stars. The longitude origin lays near the zeta Piscium, a binary star in constellation Pisces.
Each lunar month begins with a new moon (Sun and Moon conjunction). A lunar month receives its name after the zodiac sign which the Sun enters during this month. When no sign is entered during the month, then the month is considered a leap. Very rarely, it can be the occurrence of the solar month without moon conjunction. In this case, the corresponding lunar month is skipped1.
It is noteworthy that the calendrical calculations for the above four calculators are described in the Surya Siddhanta, the ancient astronomical treatise. The treatise explains the mathematical model of the heavenly bodies' motion around the static Earth. The following calculator illustrates this archaic model of the world.
Also please have a look at the calendar converters for other Hindu calendars (probably not so popular):
- Mean solar calendar: to , from
- Mean lunisolar calendar: to , from
- Day count since Kali Yuga: to, from
Mean (madhyama) calendars, unlike astronomical or true (spasta) calendars use mean times, so they don't depend on astronomical events. The mean calendars were in use before 1100 C.E.
N.Dershowitz, E.M. Reingold Calendrical Calculations Third edition ↩