Ethiopian Calendar: Principal calendar system, mainly used in Ethiopia and Eritrea

It serves as the liturgical calendar for Christians in Eritrea and Ethiopia belonging to the Orthodox Tewahedo churches, Eastern Catholic Church and Coptic Orthodox Church. It is a solar calendar which comes from the Egyptian calendar. But like the Julian calendar, it adds a leap day every four years. It begins the year on August 29 or August 30 in the Julian calendar. A seven to eight-year gap between the Ethiopian and Gregorian calendars results from an alternate calculation in determining the date of the annunciation of Jesus.

Like the Coptic calendar, the Ethiopic calendar has twelve months of 30 days plus five or six epagomenal days, which make up a thirteenth month. The Ethiopian months begin on the same days as those of the Coptic calendar. The names of the days are in Ge'ez. The sixth epagomenal day is added every four years without exception on August 29 of the Julian calendar. This occurs six months before the Julian leap day. Thus the first day of the Ethiopian year, 1 Mäskäräm, for years between 1900 and 2099 (inclusive), is usually September 11 (Gregorian). It, however, falls on September 12 in years before the Gregorian leap year. The Ethiopian New Year falls on September 11 of the Gregorian calendar. On leap years it falls on September 12.

In 1582 the Christian world changed from the Julian calendar to the Gregorian calendar. Ethiopia did not make the change. As a result, Ethiopia is seven years and eight months behind those countries that use the Gregorian calendar. Christmas and Easter fall on different dates than they would elsewhere.

In Ethiopia banks, airlines and other institutions that tourists would use run on the western calendar. Everywhere else the Ethiopian calendar is used. That may cause some confusion.