Julian Vs Gregorian Calendar Converter. The main difference between julian and gregorian calendars is that an average year in julian calendar is 365.25 days while an average year in gregorian. So, to convert from the julian calendar to the gregorian calendar, add 13 days;
It is based on a solar year of 365.2425 days and is more accurate than the julian calendar. Simply enter date in a valid calendar/date format and click โconvertโ.