The Ethiopian calendar is the principal calendar used in Ethiopia and is approximately 7-8 years behind the Gregorian calendar. It has 13 months - 12 months of 30 days each and a 13th month of 5 or 6 days.

The Gregorian calendar is the calendar used in most of the world. It was introduced in October 1582 by Pope Gregory XIII as a modification of the Julian calendar.

New Year in the Ethiopian calendar is celebrated on September 11(or September 12 in leap years) in the Gregorian calendar.