The Persian calendar is used in most countries where Persian is spoken, although some regions use different month names. The Persian calendar is the official calendar of Iran and Afghanistan, and it is one of the alternative calendars in regions such as Kazakhstan and Tajikistan.

Dates in the Persian calendar start from the year of the Hijra, which corresponds to 622 C.E. and is the year when Muhammad (PBUH) migrated from Mecca to Medina. For example, the date March 21, 2002 C.E. corresponds to the first day of the month of Farvardeen in the year 1381 Anno Persico.

The Persian calendar is based on a solar year and is approximately 365 days long. A year cycles through four seasons, and a new year begins when the sun appears to cross the equator from the southern hemisphere to the northern hemisphere as viewed from the center of the Earth. The new year marks the first day of the month of Farvardeen, which is the first day of spring in the northern hemisphere.

Each of the first six months in the Persian calendar has 31 days, each of the next five months has 30 days, and the last month has 29 days in a common year and 30 days in a leap year. A leap year is a year that, when divided by 33, has a remainder of 1, 5, 9, 13, 17, 22, 26, or 30. For example, the year 1370 is a leap year because dividing it by 33 yields a remainder of 17. There are approximately eight leap years in every 33-year cycle.

Using the PersianCalendar

Applications use a System.Globalization.PersianCalendar object to calculate dates in the Persian calendar or convert Persian dates to and from Gregorian dates.

Your application should not use a System.Globalization.PersianCalendar object as the default calendar for a culture. The default calendar is specified by the CultureInfo.Calendar property and must be one of the calendars returned by the CultureInfo.OptionalCalendars property. Currently, the System.Globalization.PersianCalendar class is not an optional calendar for any culture supported by the System.Globalization.CultureInfo class and consequently cannot be a default calendar.

Namespace: System.Globalization
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 2.0.0.0, 4.0.0.0
Since: .NET 2.0