Here you can calculate Eastern and all other moving holidays for any year in the period 326-3000 AD. The program takes into account the julian calendar (until 1582 AD) and the still valid gregorian calendar (up from 1583 AD) with their different leap year rules.
Please, notice that not all countries changed their calender in 1582. For example, in England, Scottland and the english colonies in north america (later USA) the Julian calender was valid until 1752.
Please, enter a year of interest and press the “calculate” button:
Background / History:
Our movable christian holidays depend on Easter Sunday. The date of Easter Sunday is here calculated by the the easter formula from Carl Friedrich Gauss (1777 to 1855) in a slightly modified form of Lichtenberg.
Only in the year 325 AD at the Council of Nicaea was determined that Easter sunday is the first Sunday after the first full moon in spring. Therefore the program do not accept the input of years before 326 AD, since there was no general rule for the easter calculation.
The upper limit is set by the year 3000 AD, although the gaussian Easter formula is valid for years > 3000 AD, since at some point after the year 3000 AD, the Gregorian calendar will differ more than one year from the tropical year.
This means, at this time in future a further calender correction may have to be performed.
Whether this point in time will be around the year 8000 AD or earlier in the year 3200 AD, depend on factors such as the fluctuation of the tropical year, the slow decline of the earth rotation and the definition of the tropical year. The prognose is non-trivial and is still discussed by scientists.