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Calculating the Easter Date

Easter is the most important movable feast in Christianity. How is the date determined each year?

Illustration image

An Easter Sunday date in the calendar.


How Is Easter Determined?

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.

Although Easter is liturgically related to the beginning of spring in the Northern Hemisphere (March equinox) and the Full Moon, its date is not based on the actual astronomical date of either event.

  • March 21 is the Church's date of the March equinox, regardless of the time zone, while the actual date of the equinox varies between March 19 and March 22, and the date depends on the time zone.
  • The date of the Paschal Full Moon, used to determine the date of Easter, is based on mathematical approximations following a 19-year cycle called the Metonic cycle.

Both dates may coincide with the dates of the astronomical events, but in some years, they don't.

Astronomical vs. Ecclesiastical Dates

In years in which the Church's March equinox and Paschal Full Moon dates do not coincide with the astronomical dates of these events, there may be some confusion about the date of Easter. In 2019, for example, the March equinox in the Western Hemisphere happened on Wednesday, March 20, while the first Full Moon in spring was on Thursday, March 21 in many time zones. If the Church followed the timing of these astronomical events, Easter would have been celebrated on March 24, the Sunday after the Full Moon on March 21.

However, the Full Moon date in March specified by the Church's lunar calendar, also called the ecclesiastical Full Moon, was March 20, 2019—one day before the ecclesiastical date of the March equinox, March 21. For that reason, the Easter date 2019 was based on the next ecclesiastical Full Moon, on April 18. This is why Easter Sunday 2019 was on April 21.

Earliest and Latest Easter Dates

According to the Metonic cycle, the Paschal Full Moon falls on a recurring sequence of 19 dates ranging from March 21 to April 18. Since Easter happens on the Sunday following the Paschal Full Moon, it can fall on any date between March 22 and April 25. (Note: this applies only to years 1753-2400).

Holidays Related to Easter

The dates of many Christian feasts are based on the date of Easter Sunday. For example:

Why Is Easter Celebrated in Spring?

According to the Bible, Jesus Christ's death and resurrection occurred at the time of the Jewish Passover, which was celebrated on the first Full Moon following the vernal equinox. This soon led to Christians celebrating Easter on different dates. At the end of the 2nd century, some congregations celebrated Easter on the day of the Passover, while others celebrated it on the following Sunday.

In 325 CE, the Council of Nicaea established that Easter would be held on the first Sunday after the first Full Moon occurring on or after the vernal equinox. (*) From that point forward, the Easter date depended on the ecclesiastical approximation of March 21 for the vernal equinox.

Orthodox Easter

Not all Christians observe Easter according to the Gregorian calendar; most Orthodox Christians still follow the Julian calendar.

Like the Easter date based on the Gregorian calendar, Orthodox Easter falls on a Sunday between March 22 and April 25 in the Julian calendar (years 1753-2400). In the Gregorian calendar, this corresponds to April 3 to May 10.

In some years, Orthodox Easter falls on the same day as western Easter. The next time the two Easter dates coincide will be in 2025 (April 20).

Proposed Easter Date Reforms

There have been a number of suggested reforms for the Easter date. For example, in 1997, the World Council of Churches proposed a reform of the Easter calculation to replace an equation-based method of calculating Easter with direct astronomical observation.

This would have solved the Easter date difference between churches that observe the Gregorian calendar and those that observe the Julian calendar. The reform was proposed to be implemented in 2001, but it is not yet adopted.

Another example of a proposed reform occurred in the United Kingdom, where the Easter Act 1928 was established to allow the Easter date to be fixed as the first Sunday after the second Saturday in April. However, this law was not implemented, although it remains on the UK Statute Law Database.

Earliest Easter Dates in Years 1753-2400

Gregorian CalendarJulian Calendar
March 221761April 31763
March 221818April 41790
March 222285April 41847
March 222353April 41858
March 231788April 41915
March 231845April 42010
March 231856April 51801
March 231913April 51885
March 232008April 51896
March 232160April 51942
March 232228April 51953
March 232380April 52037
  April 52048
  April 52105
Note: All Julian dates are converted to Gregorian calendar dates

Latest Easter Dates in Years 1753-2400

Gregorian CalendarJulian Calendar
April 231848May 72051
April 231905May 72271
April 231916May 72344
April 232000May 81983
April 232079May 82078
April 232152May 82135
April 232220May 82146
April 241791May 82203
April 241859May 82287
April 242011May 82298
April 242095May 82355
April 242163May 82366
April 242231May 92173
April 242383May 92230
April 251886May 92241
April 251943May 92382
April 252038May 92393
  May 102268
  May 102325
  May 102336
All Julian dates are converted to Gregorian calendar dates

(*) The resolution's exact wording is unknown, so the council's precise contribution to the process of determining the date of Easter is disputed. However, according to some historians, contemporary sources (e.g., by Epiphanius of Salamis and Socrates of Constantinople) suggest that the council decided on an Easter date after the spring equinox.

Topics: Dates, Calendar