Why does Easter change every year?
Easter is a movable feast, not a fixed Gregorian-date holiday such as Christmas. Western Easter is tied to the ecclesiastical spring equinox and the Paschal full moon, then placed on the following Sunday. Because those calendar conditions shift from year to year, Easter Sunday moves within a spring window instead of staying on one date.
Why do Western and Orthodox Easter differ?
Western churches calculate Easter from the Gregorian computus, while most Orthodox churches still determine Pascha from the Julian paschalion and then publish the result on the Gregorian civil calendar for modern use. Because the two systems do not use identical calendar rules, the dates can match exactly in some years and differ by one or more weeks in others.
What is the Paschal full moon?
The Paschal full moon is the ecclesiastical full moon used in the Easter calculation. It is not simply whichever astronomical full moon happens to be visible in the sky on a given night; it is a calendar-based reference point used by the computus. Western Easter is then assigned to the first Sunday after that ecclesiastical full moon on or after 21 March.
Is Easter based on the astronomical full moon?
Not directly. The calculation uses ecclesiastical calendar rules rather than a fresh astronomical observation each year, which is why you will often see references to the ecclesiastical equinox and ecclesiastical full moon. That distinction matters because people searching how is Easter determined often assume the date is set from live astronomy alone, when the church-calendar framework is actually the key part of the rule.
What is the earliest and latest possible Easter?
Western Easter can fall between 22 March and 25 April. Orthodox Easter, when shown on the Gregorian civil calendar, falls later overall and can extend into early May. Those limits are useful because they explain why some years produce a very early Lent and others compress the Easter season toward the end of spring.
Can Easter fall in both March and April?
Yes. Western Easter can land in either month because its valid window spans from 22 March to 25 April. That is why searches such as is Easter always in April or can Easter be in March come up so often: the answer depends entirely on the year selected.
Why does the calculator show Ash Wednesday, Good Friday, and Pentecost from Western Easter?
Those dates are shown as Western movable observances anchored to the Western Easter result because they are fixed offsets in the Western liturgical sequence. Orthodox Easter is included on this page as a comparison date, but the calculator does not try to turn that single comparison result into a full Orthodox feast table with tradition-specific terminology and transfer rules.
Can Western and Orthodox Easter ever be on the same day?
Yes. Some years align exactly, and 2025 is a straightforward example because both traditions celebrate Easter on Sunday, 20 April 2025. Same-date years are useful to spot because they remove the planning gap that appears in split-date years such as 2024 or 2026.
What is computus?
Computus is the traditional name for the rule-based method used to determine Easter Sunday. In plain language, it is the church-calendar calculation that combines the ecclesiastical equinox, the Paschal full moon, and the following Sunday rule. When people search how is Easter determined, computus is the historical and technical word for that process.
Why can the Western and Orthodox Easter gap be 0, 7, 28, or 35 days?
The gap changes because Western and Orthodox Easter are not calculated from exactly the same calendar framework. When the qualifying Sundays line up, the gap is 0 days. When they fall one week apart, the gap is 7 days. Larger gaps such as 28 or 35 days appear when the Julian-based Orthodox result ends up several weeks later once it is expressed on the Gregorian civil calendar. The calculator shows that difference directly for the selected year instead of making you compare separate holiday tables.
When will Western and Orthodox Easter be the same again?
The answer depends on the year you are checking because the two Easter calculations sometimes align and sometimes diverge. Rather than memorising a schedule, it is more reliable to enter the years you care about and compare the headline Western result with the Orthodox comparison date. That approach is especially useful for planners, schools, publishers, and families who need a practical answer for a specific future year.
How can I compare Easter dates across nearby years?
Enter the year you care about and use the nearby Easter Sundays table. It shows the selected year alongside surrounding years, with Western Easter, Orthodox Easter, and the civil-calendar gap for each row. That is useful when you are planning a recurring event, checking whether Easter is early or late in a run of years, or looking for a same-date Western and Orthodox Easter year.
Why does the calculator include Maundy Thursday, Holy Saturday, and Easter Monday?
Those dates are included because many users need the practical dates immediately around Easter Sunday, not only the Sunday itself. The calculator treats them as Western offsets from Western Easter: Maundy Thursday is three days before, Holy Saturday is one day before, and Easter Monday is one day after. Local legal holidays and church observances can still differ, so use local calendars when the exact observance rules matter.
Does this page calculate a full Orthodox movable-feast calendar?
No. The page shows Orthodox Easter as a civil-calendar comparison date, but the offset table underneath is intentionally a Western feast sequence anchored to Western Easter. A full Orthodox movable-feast calendar would need its own tradition-specific observances, terminology, and jurisdictional detail rather than being implied from one comparison date.
Does this calculator work for historical church-calendar research?
It works best for modern civil-calendar lookup and education, not for every historical jurisdictional question. The page does not model the country-by-country adoption timeline of the Gregorian calendar, and it does not claim to reproduce every local church calendar practice before the modern era. For historical liturgical research, you should still confirm against a specialist historical or church source.
