When is Easter 2018 and why does the date of Easter change every year? How do we determine the date of Easter?
Easter is a “movable feast” and does not have a fixed date; however, it is always on a Sunday.
Easter always falls on a Sunday between March 22 and April 25.
Eastern Orthodox Church
Certain Christian churches, such as many Eastern Orthodox churches, follow the Julian calendar rather than the Gregorian, either for movable feasts or for all religious observances. In this case, the observance of Easter can occur between April 4 and May 8.
What is the Golden number?
Readers often ask us about the Golden Number, which was traditionally used in calculations for determining the date of Easter. The Moon repeats the dates of its phases approximately every 19 years (the Metonic cycle), and the Golden Number represents a year in that cycle. The year of the cycle can then be used to determine the date of Easter.
To Calculate the Golden Number:
Add 1 to any given year and divide the result by 19, ensuring that you calculate to the nearest whole number; the remainder is the Golden Number. If there is no remainder, the Golden Number is 19.
For example, to calculate the Golden Number for 2018, we take 2018 and add 1, resulting in 2019, then divide it evenly by 19, giving us 106 with a remainder of 5. Therefore, the Golden Number for 2018 is 5, meaning 2018 is the 5th year of the Metonic cycle.
SOURCE: Almanac.com