Easter moves, but not randomly
2 min read · figures checked · How we check
Easter is the first Sunday after the first ecclesiastical full moon on or after 21 March. The rule is pure arithmetic, which is why a date from the sixth century can be computed exactly.
Easter Sunday is 5 April in 2026 and 28 March in 2027. The date is fixed by the Gregorian computus and can range over 35 days, from 22 March to 25 April. Every figure here is computed by the same evaluator the calculators use, from the same sourced specification, rather than researched separately for the article. Where a number is exact by definition the article says so; where it is a measurement or a convention, it says that instead.
The rule, stated plainly
Easter falls on the first Sunday after the first ecclesiastical full moon that lands on or after 21 March. Three things in that sentence do the work: the fixed date of 21 March as a stand-in for the equinox, an ecclesiastical full moon that is computed rather than observed, and the Sunday that follows it.
Because none of the three depends on looking at the sky, the whole thing reduces to integer arithmetic — the anonymous Gregorian computus, a page of divisions and remainders. That is why a calendar can print Easter for the year 2200 without anyone waiting to see the moon.
How far can it move?
From 22 March to 25 April, a span of 35 days. Both ends are rare: the earliest possible date last occurred in 1818 and the latest in 1943. In practice Easter lands in the first half of April more often than anywhere else.
| Year | Easter Sunday |
|---|---|
| 2026 | Sunday 5 April |
| 2027 | Sunday 28 March |
| 2028 | Sunday 16 April |
| 2029 | Sunday 1 April |
| 2030 | Sunday 21 April |
Why the ecclesiastical moon is not the real moon
The full moon in the rule is a tabulated one, from a cycle that repeats every 19 years. It approximates the astronomical moon and occasionally disagrees with it by a day or two. That is deliberate: a date that everyone can compute in advance is worth more to a calendar than a date that is astronomically exact but has to be observed from somewhere in particular.
Every holiday that hangs off Easter — Good Friday, Ash Wednesday, Pentecost — moves with it, which is why a year's worth of dates can shift by up to five weeks against the fixed holidays around them.
What a five-week swing actually moves
School terms in most of Europe are built around Easter, so the spring holiday can land in March one year and late April the next. Retailers plan a chocolate season that shifts by over a month against a fixed calendar. Anyone comparing one year of sales to another has to decide whether to compare by date or by proximity to Easter, and the two give different answers.
The same problem hits every derived date. Ash Wednesday is 46 days before Easter, Pentecost 49 days after. A calendar that places Easter correctly places all of them; one that hardcodes last year's date is wrong about the whole cluster.
This is why every moving holiday on this site prints the rule beside the date rather than only the date. A rule can be checked against next year; a date cannot.
Orthodox Easter is the same rule run on a different calendar. It uses the Julian reckoning for both the equinox and the moon, and the Julian calendar now runs 13 days behind the Gregorian one, so the two Easters usually fall on different Sundays and occasionally coincide. Neither is a variant of the other; they are the same definition applied to two calendars that no longer agree about what day it is.
Do the arithmetic
- 2026 calendarEvery marked day, with the rule that places it
- Days until EasterCounted from today, with the weekday
- April 2026The month Easter falls in this year