The Coptic calendar is a solar calendar used by the Coptic Orthodox Church and some other Christian communities in Egypt. It consists of 13 months: 12 months of 30 days each and an additional month of 5 days, or 6 days in a leap year. The calendar begins on the 1st of Thout, which corresponds to September 11 in the Gregorian calendar. The Coptic calendar is based on the ancient Egyptian calendar and is primarily used for religious purposes, including the determination of feast days and fasting periods. It plays a significant role in the cultural and liturgical life of the Coptic community.