Easter Day Calculator

Easter Calculation Rule:

Easter falls on the first Sunday following the first full moon that occurs on or after the vernal equinox (March 21).

Easter Sunday Date:

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1. What is Easter Date Calculation?

Easter is a moveable feast that doesn't fall on a fixed date in the Gregorian calendar. It's calculated as the first Sunday after the first full moon occurring on or after the vernal equinox (March 21). This calculation is based on ecclesiastical rules established by the Council of Nicaea in 325 AD.

2. How Does the Calculator Work?

The calculator uses the Anonymous Gregorian algorithm to determine Easter date:

a = year mod 19
b = year div 100
c = year mod 100
d = b div 4
e = b mod 4
f = (b + 8) div 25
g = (b - f + 1) div 3
h = (19a + b - d - g + 15) mod 30
i = c div 4
k = c mod 4
l = (32 + 2e + 2i - h - k) mod 7
m = (a + 11h + 22l) div 451
month = (h + l - 7m + 114) div 31
day = (h + l - 7m + 114) mod 31 + 1

This algorithm provides the date of Easter Sunday in the Gregorian calendar for any given year.

3. Importance of Easter Calculation

Details: The date of Easter determines many other important dates in the Christian calendar, including Ash Wednesday, Palm Sunday, Good Friday, Ascension Day, and Pentecost. Many secular events and holidays are also scheduled relative to Easter.

4. Using the Calculator

Tips: Simply enter any year between 1583 (when the Gregorian calendar was introduced) and 3000, then click "Calculate" to find the date of Easter Sunday for that year.

5. Frequently Asked Questions (FAQ)

Q1: Why does Easter's date change every year?
A: Easter is based on a lunisolar calendar (combining moon phases and solar year) rather than purely solar calendar dates.

Q2: What's the earliest possible date for Easter?
A: March 22 (last occurred in 1818, will next occur in 2285).

Q3: What's the latest possible date for Easter?
A: April 25 (last occurred in 1943, will next occur in 2038).

Q4: Do all Christian churches celebrate Easter on the same date?
A: No, most Orthodox churches use the Julian calendar for calculation, resulting in different dates.

Q5: Why was March 21 chosen as the vernal equinox date?
A: This was the approximate date of the equinox in 325 AD when the calculation method was established.