The Indian national calendar, sometimes called the Saka calendar, is the official civil calendar in use in India along with the Vikram Samvat calendar. It is used, alongside the Gregorian calendar, by The Gazette of India, in news broadcasts by All India Radio and in calendars and communications issued by the Government of India. The Saka calendar is also used in Java and Bali among Indonesian Hindus. Nyepi, the "Day of Silence", is a celebration of the Saka new year in Bali. Nepal's Nepal Sambat evolved from the Saka calendar.
The calendar months follow the signs of the tropical zodiac rather than the sidereal zodiac normally used with Hindu calendar.
In leap years, Chaitra has 31 days and starts on March 21 instead. The months in the first half of the year all have 31 days, to take into account the slower movement of the sun across the ecliptic at this time.
Years are counted in the Saka Era, which starts its year 0 in the year 78 of the Common Era. To determine leap years, add 78 to the Saka year - if the result is a leap year in the Gregorian calendar, then the Saka year is a leap year as well. Its structure is like the Persian calendar.