Ethiopian Calendar Converter

In short The Ethiopian calendar is the tidiest in common use: twelve months of exactly thirty days, then a thirteenth month called Pagumen with five days, or six in a leap year. That is the literal source of the tourism line about thirteen months of sunshine. The year begins at Enkutatash, on 11 September in most years and 12 September before a Gregorian leap year, and it runs seven or eight years behind the Gregorian — the gap is not drift but a different calculated date for the Annunciation, and it changes by one each September when the Ethiopian year turns while the Gregorian one does not. Leap years fall in the year before the Julian leap year, so every fourth year has a six-day Pagumen. Because every month except the last is exactly thirty days, an Ethiopian date is unusually easy to work with arithmetically, which is why the conversion here is a single formula rather than a table.