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Why Orthodox Pascha falls on a different date from Easter

Why Orthodox Pascha and Western Easter diverge, how each date is calculated, a verified table of dates to 2040, and what a mixed-calendar household should plan for.

By Orthodate Editorial12 minute read

Orthodox and Western Christians follow the same rule for dating Easter and arrive at different answers because they apply it with different astronomical tables. The rule, settled in the fourth century, is that Pascha falls on the first Sunday after the first full moon following the spring equinox. The Orthodox Church works out the equinox and the full moon using the older Julian reckoning, which has drifted from the astronomical reality by thirteen days; the West uses the corrected Gregorian one. Everything else follows from that single difference, including gaps of up to five weeks and the years in which the two coincide exactly.

At a glance

Key takeaways

  • Both traditions apply the same fourth-century rule and differ only in the astronomical tables used to locate the equinox and the paschal full moon.
  • The gap between the two dates is always zero, one, four or five weeks, because both are Sundays and the difference is a whole number of lunar and weekly cycles.
  • Nearly every Orthodox church keeps fixed feasts on the new calendar while computing Pascha on the old one, so a parish can celebrate the Nativity on 25 December and still keep Pascha in May.

1. The rule everyone agrees on

The First Ecumenical Council at Nicaea in 325 addressed a genuine problem: Christians in different provinces were keeping Pascha on different days, and some were determining it by asking their neighbours when Passover fell rather than by any common reckoning. The Council settled that the whole Church should observe it together, on a Sunday, after the spring equinox.

The formula that came out of that settlement is the one still used on both sides today. Pascha is the first Sunday after the first full moon that follows the vernal equinox. Three components, all of which sound perfectly determinate: a Sunday, a full moon, an equinox.

The difficulty is that two of the three are astronomical, and in the fourth century nobody was going to observe the moon each year and announce a date. What was adopted instead was a table — a computus — that predicted both the equinox and the full moon far in advance so that every church could calculate the same answer independently. The Alexandrian computation became the standard, and for over a thousand years it produced one date for everyone.

2. What went wrong with the table

The Julian calendar assumes a year of exactly 365.25 days. The actual solar year is about eleven minutes shorter. Eleven minutes is nothing in a lifetime and considerable over sixteen centuries: the calendar slips roughly one day every 128 years against the sun, and the spring equinox, which the computus fixes at 21 March, drifted steadily away from the day the sun actually crosses the equator.

By the sixteenth century the accumulated error was ten days, and the liturgical spring was visibly detaching from the astronomical one. The Gregorian reform of 1582 corrected it in two ways: it deleted ten days from the calendar outright, and it changed the leap-year rule so that century years are leap years only when divisible by four hundred. It also revised the lunar tables used to find the paschal full moon.

The Orthodox Church did not adopt that reform. Today the Julian calendar runs thirteen days behind the Gregorian, and the Julian computus places its notional equinox on what the civil calendar calls 3 April. Since the first full moon after that notional equinox is frequently a different moon from the first full moon after the real one, the two traditions land on different Sundays.

There is a second factor in Orthodox practice, often mentioned and frequently oversimplified: the tradition that Pascha should not precede or coincide with the Jewish Passover, following from the Gospel sequence in which the Resurrection comes after it. In the Julian reckoning this is generally satisfied automatically, and the interaction of the two considerations is part of why Orthodox Pascha is never earlier than the Western date.

3. Why the gap is always zero, one, four or five weeks

The gap between the two dates is never three days or ten. It is always a whole number of weeks, and in practice only four values occur: the same Sunday, one week later, four weeks later or five weeks later. Orthodox Pascha is never earlier.

The reason is structural rather than coincidental. Both traditions must land on a Sunday, so any difference is necessarily a multiple of seven days. And both are anchored to a lunar cycle of roughly twenty-nine and a half days, so when the two computations select different moons the result is a jump of about a month rather than a few days. Combine the two constraints and only a handful of outcomes are arithmetically available.

The practical consequence is that the years worth planning around are the five-week years. A one-week difference is a minor inconvenience for a mixed family. A five-week difference means Western Easter arrives while the Orthodox side of the household is in the middle of Great Lent, which is a genuinely different kind of problem.

4. The dates, computed rather than copied

The table below was generated directly from the two computations — the Gregorian computus for the Western date and the Julian paschalion converted to civil dates for Pascha — rather than transcribed from a list. Both are deterministic, so these dates are fixed and can be relied on.

Note how often the two coincide: five times in the sixteen years shown. Coinciding years are not rare and they are not a sign of anything changing. They simply occur when both computations happen to select the same paschal moon.

  • 2025: both on 20 April. The year of the 1700th anniversary of Nicaea, which is why it drew particular attention.
  • 2026: Western 5 April, Pascha 12 April (one week).
  • 2027: Western 28 March, Pascha 2 May (five weeks).
  • 2028: both on 16 April.
  • 2029: Western 1 April, Pascha 8 April (one week).
  • 2030: Western 21 April, Pascha 28 April (one week).
  • 2031: both on 13 April.
  • 2032: Western 28 March, Pascha 2 May (five weeks).
  • 2033: Western 17 April, Pascha 24 April (one week).
  • 2034: both on 9 April.
  • 2035: Western 25 March, Pascha 29 April (five weeks).
  • 2036: Western 13 April, Pascha 20 April (one week).
  • 2037: both on 5 April. 2038: both on 25 April.
  • 2039: Western 10 April, Pascha 17 April (one week). 2040: Western 1 April, Pascha 6 May (five weeks).

5. Why your parish keeps Christmas on 25 December and Pascha in May

This confuses people more than the underlying astronomy does, and the answer is that most Orthodox churches use two calendars at once, deliberately.

In the 1920s a number of churches adopted what is usually called the Revised Julian calendar for the fixed feasts — the ones that always fall on the same date, such as the Nativity on 25 December and the Dormition on 15 August. For the present era that calendar agrees with the Gregorian, so those parishes keep Christmas on the same day as their neighbours. The Greek, Antiochian, Romanian and Bulgarian churches and the Orthodox Church in America are largely in this group.

But almost none of them changed the paschalion. Pascha and everything that moves with it — Great Lent, Holy Week, Ascension, Pentecost — continued to be computed on the old reckoning, which is why a parish celebrating the Nativity on 25 December may still keep Pascha five weeks after its Western neighbours. Churches that did not adopt the revision at all, including the Russian Church, ROCOR, the Serbian Church, the Georgian Church and Mount Athos, keep the Nativity on 7 January by the civil calendar and use the same old paschalion for Pascha.

The one significant exception runs the other way: the Orthodox Church of Finland uses the Gregorian paschalion and keeps Pascha on the Western date. It is genuinely unusual, and it is the exception that proves the arrangement is a decision rather than a law of nature.

6. What a mixed household actually has to plan

For a couple where one person is Orthodox and the other is Catholic or Protestant, or where two Orthodox spouses belong to parishes on different calendars, the calendar is one of the few genuinely practical religious differences — and, unusually, it is entirely solvable with a diary.

Work out the pattern for the next several years rather than reacting to each one. In a coinciding year there is nothing to negotiate. In a one-week year you can usually do both, and many families simply celebrate twice. A five-week year is the one that needs a conversation, because Western Easter will fall during Great Lent for the Orthodox partner: the extended family dinner, the chocolate, the ham and the champagne will all arrive at the point of the year when one of you is fasting most strictly.

There is no single right answer and there is a wrong approach, which is to leave it until the week itself and then have the argument in front of relatives. Decide in advance which celebrations you will attend, what the Orthodox partner will and will not eat, what you will tell the family, and how you will handle the reverse case five weeks later when the other side’s Easter is long past and yours has just begun.

If children are involved, the question sharpens, because it stops being about one Sunday and becomes about which rhythm the household lives in. That is worth raising with a priest well before a wedding rather than discovering it in the second spring of a marriage.

7. What actually moves with Pascha

Pascha is not one day that shifts while everything else stays fixed. It is the hinge of the entire movable year, and a five-week difference relocates about a third of the calendar with it.

  • Great Lent, which begins on Clean Monday, seven weeks before Pascha.
  • The pre-Lenten Sundays, including Meatfare, Cheesefare and Forgiveness Sunday.
  • Palm Sunday and the whole of Holy Week.
  • Bright Week, the fast-free week immediately after Pascha.
  • The Ascension, forty days after Pascha, and Pentecost, fifty days after.
  • The Apostles’ Fast, which begins after All Saints and therefore varies in length from year to year — in some years it is more than a month and in others barely a week.
  • Traditions15 min

    Holy Week and Pascha as a couple

    The most demanding week of the Orthodox year, explained day by day, plus the practical questions couples run into about families, fasting and where to spend it.

8. Will the two dates ever be reconciled?

The subject is raised regularly and has been for a century. The World Council of Churches proposed a common formula in 1997 that would keep the Nicene rule and use modern astronomical observation for the equinox and the full moon, measured from the meridian of Jerusalem. It was not adopted. In 2025, the 1700th anniversary of Nicaea and a year in which the dates coincided, senior figures on both sides again spoke publicly about the desirability of a common date.

Nothing has been agreed, and the obstacles are less mathematical than ecclesial. Any change would have to be accepted by all the autocephalous Orthodox churches together, and the calendar question already carries a painful history: the partial adoption of the revised calendar in the 1920s produced lasting divisions in several countries, and no one is eager to repeat that.

The reasonable expectation, then, is that the present arrangement continues for the foreseeable future. Plan around the table rather than around the hope of a reform.

Map the next five springs before they arrive

Twenty minutes with a calendar removes almost every recurring difficulty this creates, and it is far easier to do in autumn than in the week itself.

  1. Step 1

    Write down the pattern for five years

    List both dates for each of the next five years and mark each as coinciding, one week apart or five weeks apart. The five-week years are the only ones that need a plan; everything else is a minor scheduling matter that will resolve itself.

  2. Step 2

    Decide the five-week years now

    For each year where Western Easter falls inside Great Lent, agree in advance which gatherings you will attend, what the fasting partner will eat, and what you will say if asked. Settling it in October costs nothing; settling it at the table costs a great deal.

  3. Step 3

    Check what your own parish keeps

    Confirm whether your parish uses the new calendar for fixed feasts and whether anything in your family follows the old one. A household can easily contain both the 25 December Nativity and a 7 January one, and knowing which applies where prevents a repeated annual misunderstanding.

  4. Step 4

    Block Holy Week in the diary a year out

    Holy Week is the least flexible week in the Orthodox year and it moves. Put it in the calendar as soon as the date is known, along with Ascension and Pentecost, and book travel and time off around it rather than discovering the clash in March.

Common questions

Why is Orthodox Easter on a different date?

Both traditions follow the same fourth-century rule, that Pascha is the first Sunday after the first full moon following the spring equinox. The Orthodox Church locates the equinox and the full moon using the older Julian tables, which have drifted thirteen days from astronomical reality, while the West uses the corrected Gregorian ones. It is a difference of arithmetic, not of belief.

When is Orthodox Pascha in 2027?

Sunday 2 May 2027, five weeks after Western Easter on 28 March. That is one of the widest gaps possible and means Western Easter falls during Great Lent for Orthodox Christians, which is worth planning around in a mixed family.

Do Orthodox and Western Easter ever fall on the same day?

Often. They coincided in 2025 and will again in 2028, 2031, 2034, 2037 and 2038. Coinciding years occur whenever both computations happen to select the same paschal moon; they are not a sign that anything has changed.

Why is the difference always a whole number of weeks?

Because both dates must be Sundays, so any gap is a multiple of seven days, and both are anchored to a lunar cycle of about twenty-nine and a half days, so selecting a different moon moves the date by roughly a month. Only zero, one, four and five weeks are arithmetically available, and Orthodox Pascha is never the earlier of the two.

Why does my parish celebrate Christmas on 25 December but Pascha in May?

Most Orthodox churches use two calendars deliberately. The fixed feasts, including the Nativity, follow the Revised Julian calendar, which currently agrees with the civil one. Pascha and everything that moves with it are still computed on the old paschalion, which is why the two can be weeks apart.

Will the Orthodox and Western dates ever be unified?

It has been proposed repeatedly, including a common astronomical formula in 1997 and renewed discussion around the 1700th anniversary of Nicaea in 2025, but nothing has been agreed. The obstacles are ecclesial rather than mathematical, since any change would need acceptance by all the autocephalous churches and the calendar question carries a difficult history.

Which Orthodox churches use the Julian calendar for everything?

The Russian Church, ROCOR, the Serbian and Georgian churches and the monasteries of Mount Athos keep both fixed feasts and Pascha on the old reckoning, so the Nativity falls on 7 January by the civil calendar. The Greek, Antiochian, Romanian and Bulgarian churches and the Orthodox Church in America use the revised calendar for fixed feasts but the old paschalion for Pascha.

Sources and further reading

Pastoral practice can vary by diocese and jurisdiction. For questions about your circumstances, speak with the priest responsible for your pastoral care.