what is the difference between the julian and gregorian calendar?
The Julian year is, therefore, on average 365.25 days long. ... (Even then, the Gregorian calendar diverges from astronomical observations by one day in 3,030 years). The difference in the average length of the year between Julian (365.25 days) and Gregorian (365.2425 days) is 0.002%, making the Julian 10.8 minutes longer.