[Math Lair] Calculating the Date of Easter

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How do you calculate the date of Easter? Calculating the date of Easter for any year involves knowing that Easter falls in the first Sunday following the Paschal Full Moon (which doesn't always coincide exactly with the real or astronomical full moon). If the Paschal Full Moon falls on a Sunday, then Easter is the following Sunday. To calculate the date of the Paschal Full Moon, add 1 to the remainder obtained by dividing the year by 19 and using the table below to find the date.

For example, for the year 2000, the remainder is 6, which means that the Paschal Full Moon falls on April 18th. You would then figure out which day of the week that is. April 18th, 2000 is a Tuesday. Therefore, Easter would fall on the following Sunday, April 23rd.

What is the earliest date that Easter can fall? What is the latest?

Year (modulo 19) + 1Paschal Full Moon Date
1April 14
2April 3
3March 23
4April 11
5March 31
6April 18
7April 8
8March 28
9April 16
10April 5
11March 25
12April 13
13April 2
14March 22
15April 10
16March 30
17April 17
18April 7
19March 27

Another Easter-related mathematics page.

Some information about calendars