Western & Orthodox Easter Date Calculator
Enter a year to calculate Western Easter and Orthodox Pascha on the Gregorian civil calendar. The tool also compares the dates, lists related movable feasts, and finds the next year when both traditions share Easter Sunday.
Western and Orthodox EasterWestern: March 28, 2027; Orthodox: May 2, 2027
- Orthodox Easter Sunday
- May 2, 2027
- Western Easter Sunday
- March 28, 2027
- Difference between Easter dates
- 35
- Same-date status
- Different dates
- Next shared Easter
- April 16, 2028 (2028)
Movable-feast timeline
| Tradition | Observance | Date |
|---|---|---|
| Western | Ash Wednesday | February 10, 2027 |
| Western | Palm Sunday | March 21, 2027 |
| Western | Good Friday | March 26, 2027 |
| Western | Easter Sunday | March 28, 2027 |
| Western | Ascension | May 6, 2027 |
| Western | Pentecost | May 16, 2027 |
| Orthodox | Clean Monday | March 15, 2027 |
| Orthodox | Lazarus Saturday | April 24, 2027 |
| Orthodox | Palm Sunday | April 25, 2027 |
| Orthodox | Great Friday | April 30, 2027 |
| Orthodox | Pascha | May 2, 2027 |
| Orthodox | Ascension | June 10, 2027 |
| Orthodox | Pentecost | June 20, 2027 |
Western Easter uses the Gregorian computus; Orthodox Easter uses the Julian computus converted to the Gregorian civil calendar.
The movable-feast dates shown are standard offsets from Easter or Pascha and may differ where observances are transferred locally.
How to use this calculator
- Enter a year from 1583 through 4099.
- Choose whether to show Western dates, Orthodox dates, or both.
- Read the Easter Sunday result and the date difference.
- Use the timeline table for Ash Wednesday, Palm Sunday, Good Friday, Ascension, and Pentecost dates.
How the Easter dates are calculated
Western Easter is calculated with the Gregorian computus commonly called the Meeus/Jones/Butcher algorithm. For a year Y, the algorithm finds the ecclesiastical full moon after the church's fixed March equinox rule and then returns the following Sunday. The calculation is arithmetic, not an observation of the sky.
The Western formula uses these integer steps: a = Y mod 19, b = floor(Y / 100), c = Y mod 100, d = floor(b / 4), e = b mod 4, f = floor((b + 8) / 25), g = floor((b - f + 1) / 3), h = (19a + b - d - g + 15) mod 30, i = floor(c / 4), k = c mod 4, l = (32 + 2e + 2i - h - k) mod 7, and m = floor((a + 11h + 22l) / 451). The month is floor((h + l - 7m + 114) / 31), and the day is 1 + ((h + l - 7m + 114) mod 31).
Orthodox Easter is first calculated in the Julian calendar: a = Y mod 4, b = Y mod 7, c = Y mod 19, d = (19c + 15) mod 30, e = (2a + 4b - d + 34) mod 7, with the Julian month floor((d + e + 114) / 31) and day 1 + ((d + e + 114) mod 31). The Julian date is then converted through a Julian Day Number and back to the Gregorian civil calendar, so the tool does not assume a fixed 13-day offset.
Why the dates differ
The two traditions use related rules but different calendars and lunar tables. Western Easter always falls from March 22 through April 25 on the Gregorian calendar. Orthodox Easter may appear in April or May on the Gregorian civil calendar because the Julian calendar is currently behind the Gregorian calendar and because the Paschal full moon tables can differ.
The difference can be zero days when the two dates coincide, or it can be one, four, or five weeks. The next shared Easter row searches forward one year at a time and stops at the first year whose Gregorian civil dates are the same.
Movable feasts and limits
The timeline is built by adding fixed day offsets to Easter or Pascha. Western dates include Ash Wednesday at minus 46 days, Palm Sunday at minus 7, Good Friday at minus 2, Ascension at plus 39, and Pentecost at plus 49. Orthodox dates include Clean Monday at minus 48 days, Lazarus Saturday at minus 8, Palm Sunday at minus 7, Great Friday at minus 2, Ascension at plus 39, and Pentecost at plus 49.
This calculator leaves out astronomical full moons, local calendar reforms, and transferred-observance policies. Dates before a place adopted the Gregorian calendar are shown on the proleptic Gregorian civil calendar so that every year is handled consistently.
Worked example
For 2027, the Gregorian computus gives Western Easter on March 28, 2027. The Julian computus gives Orthodox Pascha on April 19 in the Julian calendar, which converts to May 2, 2027 on the Gregorian civil calendar.
The Orthodox date is 35 days after the Western date, so the same-date status is different dates. Searching ahead from 2027 finds the next shared Easter on April 16, 2028.
Common questions
How is the date of Easter calculated?
This calculator uses ecclesiastical computus rules. Western Easter uses the Gregorian Meeus/Jones/Butcher algorithm, while Orthodox Easter uses the Julian Paschal calculation and converts that Julian result to a Gregorian civil date.
Why do Western and Orthodox Easter sometimes differ?
The traditions use different calendars and different ecclesiastical lunar tables. Those differences can place the Paschal full moon and the following Sunday in separate weeks, even though both traditions are applying a church calendar rule rather than observing the astronomical full moon directly.
Can Catholic and Orthodox Easter occur on the same day?
Yes. When the Gregorian civil dates produced by the two computus procedures match, Western Easter and Orthodox Pascha fall on the same Sunday. The calculator searches forward from the year entered to find the next shared date within the supported range.
Why is Orthodox Easter converted from the Julian calendar?
The widespread Orthodox Paschal rule is stated on the Julian calendar, but most civil planning uses Gregorian dates. Converting through a Julian Day Number preserves the correct calendar offset as it changes across centuries.
What are the earliest and latest possible Easter dates?
Western Easter ranges from March 22 through April 25 on the Gregorian calendar. Orthodox Pascha can appear later on the Gregorian civil calendar, including dates in May, because the Julian calendar and Paschal tables differ from the Gregorian system.
How are Ash Wednesday, Ascension, and Pentecost dated?
They are counted from Easter Sunday. This calculator dates Ash Wednesday 46 days before Western Easter, Ascension 39 days after Easter, and Pentecost 49 days after Easter; the Orthodox timeline uses its corresponding offsets from Pascha.