Why do 250 million Christians celebrate Christmas on January 7?

EXPLAINEROrthodox and Coptic Christians don’t believe Jesus was born on a different day; they just use a different calendar.Published On 7 Jan 2026Millions of Christians, including those in Eastern Europe and across the Arab world, such as Palestine and Egypt, are celebrating Christmas today.Christmas Day commemorates the birth of Jesus Christ, who was born in Bethlehem.However, for these communities, which number about 250 million people, the most important day of the season is not December 25, but January 7. In this visual explainer, Al Jazeera illustrates what cultural and historical reasons led to this difference in Christmas celebrations.Why are there two Christmases?The reason some Christians celebrate Christmas on January 7 is not because they believe Jesus was born on a different day, but because they are using a different calendar.The difference in the timing of Christmas stretches back to 1582, when Pope Gregory XIII ruled that the Catholic Church should follow a new calendar, called the Gregorian calendar, to replace the less accurate Julian calendar.The Julian calendar, which was introduced by Julius Caesar in 46 BC, overestimated the solar year by 11 minutes, causing the seasons to eventually drift out of place.Where the Julian calendar loses one day every 128 years, the Gregorian calendar loses one day every 3,236 years, making it a much more accurate approximation of a true solar year.To get back on track, the world had to essentially skip 10 days to make up for the missing time that had accumulated over the 15 centuries.While most of the world adopted the new Gregorian calendar, many Orthodox and Eastern Christian churches have stayed with the Julian calendar to maintain their traditions.(Al Jazeera)Fast forward to today, and the Julian calendar is currently 13 days behind the Gregorian calendar. This means that December 25 on the Julian calendar actually falls on January 7 on our modern calendars.