This formula calculates the date that Orthodox Easter will be celebrated for any "normal year." However, as with any Calendrical Calculation, programmers need to be aware of certain limitations.

• These results provide dates for Orthodox Easter Sunday as determined by many Orthodox and Coptic faiths. The formula normally used in the UK and many Western Christians is listed on a separate page.
• The modern (Gregorian) calendar was not used until 15 Oct 1582, and many countries retained the old (Julian) calander for centuries afterwards. The formula calculates Gregorian dates - The UK switched calendars in 1752 and the formula can only be used in the UK for dates after 1752.

Public Function OrthodoxEaster(ByVal dat As Date) As Date
 Dim yyyy As Integer = dat.Year
 Dim a, b, c, d, e, f, g, h As Integer
 Dim Jul2Greg As Integer
 a = yyyy Mod 19
 b = yyyy Mod 4
 c = yyyy Mod 7
 d = 19 * a + 16
 e = d Mod 30
 f = 2 * b + 4 * c + 6 * e
 g = f Mod 7
 h = e + f
 Dim eDate As New Date(yyyy, 3, 21, 12, 0, 0, 0)
 eDate = DateAdd(DateInterval.Day, h, eDate)
 Jul2Greg = Int((Int(yyyy \ 100) * 3) / 4) - 2
 eDate = DateAdd(DateInterval.Day, Jul2Greg, eDate)
 Return eDate
End Function
  

 

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