The Coptic (Egyptian) calendar is an evolution of the Ancient Egyptian Calendar. It has the same month structure (12 months of 30 days each) and differs by an additional day in the intercalary month. The additional day is added every 4 years, just like in Julian calendar. So the intercalary (13th) month consists of 5 days in an ordinary year and 6 days in a leap year.
The additional day was introduced by the Ptolemy III (Egyptian pharaoh 246-222 BCE) in 238 BCE, but it was sabotaged by priests and people and abandoned until 25 BCE.
The Coptic calendar has 7-day week since about 3 century CE, for thousands of years before the Egyptians used 10-days decades instead of weeks.1
The calendar is still used by the Coptic Orthodox Church and used by the farming populace in Egypt. Coptic years are counted from August 29th, 284 CE 2, the year Diocletian became Roman Emperor.
The calculator below converts a Coptic date to a Gregorian date.
Coptic date to Gregorian date
The following calculator performs the inverse conversion from a Gregorian date to a Coptic calendar date.
Gregorian date to Coptic date
Week day name
The Coptic calendar summary
Days in a year
1st century CE
19th century CE, still in use by the Coptic Orthodox Church