Easter falls on the first Sunday after the Full Moon date, based on mathematical calculations, that falls on or after March 21. If the Full Moon is on a Sunday, Easter is celebrated on the following Sunday.

What is the rule for when Easter falls?

Specifically, Easter is celebrated on the first Sunday following the full Moon that occurs on or just after the spring equinox. Yes, its a bit confusing at first read! Lets break it down: In 2021, the spring equinox happens on Saturday, March 20. The first full Moon to occur after that date rises on Sunday, March 28.