The date of Christian Easter: how to calculate it for 2027

How Easter Sunday is determined

The calculation uses two phenomena: the spring equinox and the phases of the Moon. These are the steps:

1. start from the spring equinox, which astronomically usually falls on 20 or 21 March;
2. take the first ecclesiastical full moon that falls on or after 21 March;
3. the first Sunday after that full moon is selected as Easter Day.

How to calculate Easter in 2027

For 2027 the method produces Sunday 28 March:

• the astronomical spring equinox falls on Saturday 20 March 2027, but the ecclesiastical computus always uses 21 March;
• the first qualifying ecclesiastical full moon falls on Monday 22 March. In this case it also shares the civil date of the astronomical full moon, which occurs on 22 March at 10:44 UTC;
• the first following Sunday is 28 March 2027, the date of Western Easter.

The ecclesiastical full moon is not always the astronomical one

When calculating the full moon, the Church uses an ecclesiastical calendar based on the epact, the conventional age of the Moon at the beginning of the year. Its phases are determined from tables and need not coincide with the astronomical phases.

The difference normally does not alter the chosen Sunday, especially when the astronomical full moon is well away from 21 March. At the boundary, however, the two approaches can produce very different results.

This happened in 2019. The astronomical equinox occurred on 20 March and the astronomical full moon in the early hours of 21 March, which by those two instants alone would have pointed to Sunday 24 March. In the ecclesiastical calendar, however, the March tabular full moon fell before the 21st. The calculation therefore had to wait for the full moon of 18 April, and Easter fell on 21 April 2019.

Early, medium or late Easter

We can calculate the range in which Easter Day varies. The earliest limit is 22 March: if 21 March were a Saturday and also the ecclesiastical full moon, the following Sunday would be the 22nd.

The latest limit is 25 April. If the preceding ecclesiastical full moon were on 20 March, the calculation would have to wait for the next lunation; if that qualifying date were itself a Sunday, the rule would require the next Sunday, reaching 25 April.

According to where Easter falls within this range, it is described as:

• early Easter: from 22 March to 2 April;
• medium Easter: from 3 to 13 April;
• late Easter: from 14 to 25 April.

Other Christian observances are derived from this date:

• before: Ash Wednesday falls 46 days before Easter Sunday and opens Lent;
• after: Pentecost is the fiftieth day when Easter itself is included, or 49 days later.

This matters when we plan our trips because Easter and Easter Monday move through the calendar each year. My preferred situation is a late Easter between 20 and 23 April: depending on the weekdays, Easter Monday can sit close to Italy's Liberation Day on 25 April. If Easter reaches 24 or 25 April, however, the opportunities overlap and the possible holiday break becomes shorter.

Easter dates in 2027 and 2028

In 2023 Easter fell on 9 April.