Ethiopia’s calendar is neither ancient nor newbecause it is an eternal image of tropics and sun. Therefore, it brings three categories of fouryears. Category A is the first year that begins a day late. New Year begins on Meskeram 1, when September is 12. Category B is the second and third years in which each of them has similar beginning and ending days. New Year of each begins on Meskeram 1, when September is 11; and ends on Pagume 5, when September is 10. Category C is the fourth year that ends by having a day more. This category year three is traditionally known as leap year. It begins on Meskeram 1, when September is 11 and ends on Pagume 6, when September is 11. Categories A and B are subset of four years that each year has a period of 365 days. And category C is a subset of four years that has a period of 366 days.