How is Easter day calculated?

short answers for big questions

Easter is one of the most important Christian religious festivities. On Easter day, millions of Christians all around the world celebrate the Resurrection of Jesus Christ. However, it is not easy at all to calculate the Easter Day. Easter is celebrated on the first Sunday after the first full moon that happens after the vernal equinox. As these conditions vary a lot, it can happen from March 22 to April 25. But, this event seldom happens on the ends of this interval of time.

Easter Bunny

How is it calculated?

In Latin, the calculation of the Easter Date is known as computus. There are several mathematical algorithms all of which are too complex to calculate the day and the month when Easter takes place. As an example, for all of these who want to try here it is the Meeus/Jones/Butcher algorithm:

  • a = MOD(ANO;19)
  • b = ANO \ 100
  • c = MOD(ANO;100)
  • d = b \ 4
  • e = MOD(b;4)
  • f = (b + 8) \ 25
  • g = (b - f + 1) \ 3
  • h = MOD((19 × a + b - d - g + 15);30)
  • i = c \ 4
  • k = MOD(c;4)
  • L = MOD((32 + 2 × e + 2 × i - h - k);7)
  • m = (a + 11 × h + 22 × L) \ 451
  • MÊS = (h + L - 7 × m + 114) \ 31
  • DIA = MOD((h + L - 7 × m + 114);31) + 1
(MOD is the remainder of an integer division)

In order not to do all these tasks and if we really want to know the Easter day, it is enough for you to introduce, in the following table, the years that you want to find, then you press calculate and we do the rest!




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