Why are Catholic and Orthodox Easters different?

Basket of Orthodox Easter eggs
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You may have looked at the calendar recently and realized most people celebrated Pascha already. Yet the Orthodox won’t celebrate it until April 28th this year. Some years “Orthodox Easter” ends up nearly five weeks after the Catholic and Protestant celebration of the Resurrection. Yet other times, we celebrate our Lord’s Resurrection on the same day. What in the world is going on here?

In this post, we explain why the Orthodox typically celebrate Pascha later than the rest of Christianity. Buckle up – this will get interesting!

Two different Easters?

Easter, or Pascha (which means Passover) as we refer to it in the Orthodox Tradition, is a feast commemorating the Holy Resurrection of our Lord and God and Savior Jesus Christ. More often than not, Orthodox Christians find themselves celebrating this feast on a different date than the rest of Christianity. The reason why is rather complex, but it all boils down to two factors:

  1. Different ecclesiastical calendars
  2. Orthodox adherence to Holy Tradition

Ecclesiastical calendars

First, we’ll give a quick explanation of the difference between the calendars. Then, for those of you interested, we dive a bit deeper.

The simple answer: The Orthodox Church continues to follow the Julian calendar when calculating the date of Pascha. However, the rest of Christianity uses the newer Gregorian calendar. Due to the way the calendars were formulated, the Gregorian calendar is thirteen days ahead of the Julian calendar.

From Julian to Gregorian

Proposed by Julius Caesar in 46 B.C., the Julian calendar served as the predominant calendar for most of the Western world. It measures the tropical year at 365.25 days, and its calendar year ends up being about 10.8 minutes longer than the Gregorian calendar year. This means that, over the centuries, the Julian calendar drifted and created a discrepancy between dates of observed equinox times. For example, over the thirteen centuries the Julian calendar was in effect, the date of the vernal equinox slid to 10 March, whereas the calculation of the date of Pascha was 21 March.

In 1582, Pope Gregory XIII commissioned a reform of the Julian calendar. He named this new calendar after himself; hence, the Gregorian calendar. Astronomers of the time asserted these reforms corrected the issues found within the Julian calendar. Eventually, it became internationally accepted in Western Christianity and in secular society. However, the Orthodox Church vigorously opposed its use for centuries. This resulted in the West and East celebrating all feast days on different dates; the Orthodox celebrations always fell thirteen days behind those of Western churches.

But all other holidays are the same…

You may have noticed we only celebrate Pascha and the feast days connected to it (Pentecost and the Ascension) on different dates. But otherwise, the rest of the dates match up. Christmas, Thanksgiving, Theophany, the Dormition, etc. Why is this?

In 1923, representatives from some (not all) Orthodox churches, held an inter-Orthodox congress in Constantinople. This congress made the very controversial decision to institute a revised calendar. This calendar was essentially the same as the Gregorian calendar, except for the dates surrounding Pascha. Those dates, they decided, would be calculated according to the original Julian calendar.

This is why a fair number of Orthodox churches celebrate most feast days at the same time as Western Christians.

Orthodox adherence to Holy Tradition

The other factor that explains the difference in Easter dates is that the Orthodox Church continues to adhere to Holy Tradition, whereas the Catholics do not. Specifically, the rule set forth by the First Ecumenical Council of Nicea in 325 A.D. During this council, the Church Fathers clarified that Pascha must take place after the Jewish Passover. Otherwise, we would not be maintaining the Biblical sequence of Christ’s Passion. Unfortunately, most of Christianity ignores this requirement, and many a time they unwittingly end up celebrating Christ’s Resurrection before He was even crucified.

For many people this is confusing and frustrating. Especially for people with family members who are not Orthodox. They often wonder why we have to celebrate this important holiday at different times. In order to better understand why, let’s take a look at how we calculate the date of Pascha.

How we determine the date of Pascha

Here’s an interesting fact: during the first three centuries of Christianity, we did not have a universal date for celebrating the Resurrection of Jesus Christ! Depending on where you lived, the date you celebrated Pascha was different. Some early Christians celebrated Pascha on the first Sunday after Jewish Passover, while others celebrated at the same time as Passover.

During the First Ecumenical Council in 325 A.D., the Church Fathers discussed this issue. They decided on the following formula for deciding the date of Pascha:

We celebrate Pascha on the first Sunday after the first full moon following the vernal equinox; and we always celebrate after Jewish Passover. As we mentioned before, the date of the vernal equinox is set on March 21 (April 3 on the Julian calendar). So, for the Orthodox, Pascha is typically the first Sunday after the first full moon after April 3, so long as that date comes after Jewish Passover.

Pretty complex, isn’t it?

Occasionally, the calendars end up overlapping, and we do celebrate Pascha on the same day. This happens only during years when the first full moon after the vernal equinox (March 21) comes so late that it comes as the first full moon on both calendars. This happened in 2010, 2011, 2014, and 2017. But it won’t happen again until approximately the year 2034.


The Orthodox Church usually celebrates Easter later than the Catholic churches – anywhere from one to five weeks later. We celebrate later for two main reasons: 1) we follow a different calendar; and 2) we adhere to Holy Tradition. While the situation is actually far more complex than the picture we’ve painted for you here, this at least outlines the basic causes behind the date discrepancy everyone keeps asking about!

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