The Parsi calendar, also known as the Zoroastrian calendar or the Shahenshahi calendar, is a calendar system used by the Zoroastrian community. The Parsi calendar is a solar calendar, which means it is based on the movement of the sun.

The Parsi calendar has 12 months, and each month is named after a specific star or constellation. The first month of the Parsi calendar is Farvardin, and the Parsi year begins on the vernal equinox, which usually falls on March 21.

The Parsi calendar is used to determine the dates of Zoroastrian festivals and events, including Navroz, which is the Parsi New Year. Navroz is celebrated on the first day of Farvardin and usually falls on March 21 or 22.

The Parsi calendar is approximately 200 years behind the Gregorian calendar, which is the calendar system used in most parts of the world. This means that the dates of Parsi festivals and events do not correspond to the same dates in the Gregorian calendar each year. For example, Navroz, which falls on March 21 or 22 in the Gregorian calendar, falls on a different date in the Parsi calendar each year.