Easter is one of the most important feast days in Christianity, celebrating the events around Jesus’ crucifixion and resurrection. It comes at the end of Holy Week which lasts seven days. However, it is a moveable feast – the exact date moves from year to year and is determined by a mathematical calculation of the lunar and solar cycles.
To put it simply, Easter falls on the first Sunday after the first full moon – on or following the spring or vernal equinox, set by the church as being March 21. Which means that Easter can occur anytime between March 22 and April 25.
This year, Easter Sunday falls on April 20, 2025 – three weeks later than last year. Good Friday will be on April 17, and Easter Monday on Monday April 21. While Easter is a public holiday in many parts of the world, it is not a federal holiday in the United States although some businesses close and the US stock market is closed for trading on Good Friday.
How the date for Easter is determined
The method for determining the date for the Easter celebration was established by the Council of Nicaea in 325 AD. Neither the spring equinox nor the Paschal Moon used to calculate when the feast day will occur are the actual ones. The actual spring equinox can fall on any day between March 19 and 22. The date of the Paschal Moon, the first full moon on or after March 21, is set by the Metonic cycle, a 19-year cycle defining 19 specific days when the Paschal Moon can occur.
The calculation allows the church to set the date well into the future. Under the Julian calendar, the math was pretty simple but the Gregorian calendar complicates matters with leap years, which contains an additional day (Feb. 29). The Royal Museums Greenwich breaks down the full algorithm used to calculate the date for Easter.
Not all Christians celebrate Easter on the same day
Most Orthodox Christians still use the Julian calendar to calculate when Easter will be celebrated. While they use the same dates between March 22 and April 25, those dates correspond to April 3 and May 10 in the Gregorian calendar. There are some years when both Easters fall on the same day, the next time will be April 5, 2026.
