The Iranian Calendar, also known as the Persian Calendar, is a solar calendar used in Iran and Afghanistan. It consists of 12 months, with the first month, Farvardin, beginning on the vernal equinox, marking the start of spring. The calendar is highly accurate, aligning closely with the solar year, and is used for both civil and religious purposes. Each month in the Iranian Calendar has either 29 or 30 days, totaling 365 days in a common year. To account for the extra quarter of a day, a leap year occurs every four years, adding an additional day to the last month, Esfand.