If you’re a Catholic, and it’s getting close to Lent, you’re almost certain to hear people say something like “Easter sure is late this year” — and usually dozens of times.
Now, if you’re anything like The Pillar’s newsroom, you probably don’t recall from year to year when exactly Easter falls.
In fact, before doing some research, most of us didn’t even know how early or late Easter could be each year.
But why does the date of the Church’s Resurrection feast vary so much from year to year? What are the earliest and latest dates on which Easter (and Ash Wednesday) can fall?
And is Easter actually especially late this year?
With Ash Wednesday (finally?) around the corner, we’ve decided to answer a few questions.
So The Pillar looks at the numbers.
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Unlike fixed solemnities like Christmas, the date of Easter changes significantly from year to year. According to the calendar used by the Latin Catholic Church, the date of Easter can be as early as March 22 or as late as April 25, a span of 34 days.
In 2025, Easter falls on April 20, near the end of that range.
To get a sense of how often Easter falls on each of its possible dates, The Pillar calculated the date for Easter for the next 500 years, and plotted how often it fell on each possible date.
Including this year, Easter will fall 15 times on April 20 between now and the Year of our Lord 2524, which makes 3% of the total Easters under consideration — a fairly average share of Easters among the dates in the “Paschal span.”
Because April 20 comes so late in the range in which Easter can fall, Easter will fall in the next five centuries on an earlier date in 88% of years, 439 out of the next 500.
That means Easter really does come pretty late this year.
Ash Wednesday always falls 46 days before Easter — six full weeks plus four days. That makes the timing of Ash Wednesday simply a matter of arithmetic, dependent upon the date of Easter.
Lent is commonly described as lasting 40 days, and that works if you don’t count the six Sundays. By the calendar, it’s 46 days.
Ash Wednesday can fall as early as February 5th or as late as March 10th. In the next five centuries, Ash Wednesday will be earlier than it is this year 88% of the time.
But how is the date of Easter calculated, and why does its date vary within a range?
That answer goes back all the way to the crucifixion and resurrection of Jesus, as recounted in the Gospels.
The events of the Passion took place over the course of the Jewish feast of Passover. As early Christians celebrated the death and resurrection of Christ, they faced a question: Whether they should hold the celebration specifically on the date of Passover or on Sunday, the day of the week on which Jesus rose from the dead.
The beginning of Passover is always in the evening of the 14th day of the month of Nisan in the Hebrew calendar, which is a strictly lunar calendar.
Since each month of the Hebrew calendar begins with the new moon, Passover always begins at full moon, on the evening of the 14th day of the lunar month.
But the full moon can begin on any day of the week, which means that Passover can begin any day of the week.
That meant if early Christians celebrated Easter at the time it fell within Passover, they would be celebrating Easter on various days of the week in different years. But on the other hand, if they always celebrated Easter on a Sunday, the celebration of Easter would not line up with Passover.
In the second century, debate over when to celebrate Easter became known as the "Quartodeciman controversy," derived from the Latin word for 14 — because the issue was the 14th day of the Hebrew month of Nisan.
Christians in the East, particularly in Asia Minor, what is today the nation of Turkey, celebrated Easter on the 14th day of Nisan, while Christians in the rest of the Roman Empire celebrated it on Sunday.
St. Polycarp was among the Christians from Asia Minor who celebrated Easter on the 14th. Around 150 AD, he went to Rome to make his case to the pope, but he failed to persuade Pope St. Anicetus.
Today, the date of Easter might seem like a minor issue, but it was something the early Church took very seriously. In fact, around 190 AD, Pope St. Victor I excommunicated Christians who celebrated Easter on the 14th, and insisted that it must be celebrated on Sunday.
But even Easter Sunday uniformity wasn’t a cut-and-dry issue.
Because if you were going to celebrate Easter on Sunday, you had to know which one. And calculating that is pretty complex
The Romans used a solar calendar based on 12 months, but the Hebrew calendar — which formed the basis for Passover — was a lunar calendar, which kept roughly in line with the solar calendar by adding a 13th month, Adar II, in 7 out of every 19 years.
The difference made it unclear to the early Christians when Easter should be celebrated, with a lot of local variability in early centuries.
Nerd alert sidebar: There are 12.36 lunar cycles in a solar year. So if you base your calendar on lunar months, you either have to make an adjustment of some sort to fit the solar year, or your months will move in relation to the solar seasons by roughly one month every three years. Imagine if over the course of 18 years, January went from being a winter month to a summer month!
To resolve all the complexity around that issue, the bishops of the Council of Nicea, in 325 AD, decided to set fixed rules for calculating the Paschal commemoration.
The council ruled that Easter should:
always be celebrated on a Sunday,
that it should be after the first full moon following the spring equinox —the day when daylight and night hours are equal.
and that it should be calculated independently from Passover.
Different parts of the world came up with slightly different calculations based on these rules, and so for centuries, Easter continued to be celebrated on different dates in different parts of Christendom.
But by the high middle ages, with better communication across the Church, Christians were pretty much on the same page when it came to the date of Easter.
Regularizing the calculation of Easter involved a few simplifications to the astronomical issues at play.
Rather than using the precise astronomical equinox, the Church decided to set March 21 as a kind of “liturgical equinox” for the purpose of calculating Easter, while the scientific equinox can actually vary between March 19 and March 21.
The Church also settled on a slightly simplified system for calculating the date of the full moon.
Called the “Golden Number system,” the idea was based on the fact that every 19 years, the phases of the moon line up almost exactly on the same days of the 365 day solar calendar.
Jumping from that point, the system assumes that there are 235 lunar months in 19 solar years, and ignores the small variations along the way.
The resulting difference between the “liturgical full moon” and the astronomical full moon each day is sometimes one to two days, but as with the simplification of the equinox, the system allowed pre-modern Churchmen without access to computers to calculate easily the annual date of Easter.
As a result of those workarounds, the Church calculates the date of Easter to fall on the first Sunday after the first liturgical full moon after March 21.
But as many Catholics are aware, most Eastern Churches celebrate Easter on a different date than the Western Church. How is their calculation of Easter different?
The Eastern calculation of Easter is actually very similar to the Western one, and the biggest difference has nothing to do with the lunar calculations which factor into determining the date of Easter.
Rather, the key difference springs from the Gregorian reforms to the solar calendar, which were implemented by Pope Gregory XIII in 1582.
See in that year, Pope Gregory promulgated a new calendar, to fix a small issue with the calendar in use at the time — the Julian calendar, which went back to the reign of Julius Caesar, before the birth of Christ.
The Julian calendar provided a leap year every four years, making each year, on average, 365.25 days long.
But the Earth actually takes 365.2422 days to complete one orbit around the sun. That meant that every 128 years, the Julian calendar was off from the solar year by one day.
That doesn’t seem like much, but by 1582 there had been more than 12 sets of 128 days since Julius Caesar had implemented his own calendar.
By Gregory’s time, the calendar had drifted almost half a month against the actual seasons.
Pope Gregory’s calendar brought the Western calendar back in line with the solar year, by requiring the calendar of 1582 to drop the days between October 4 and October 14.
After that, to keep on track, the Gregorian calendar added leap years in century years divisible by 400, in addition to ones coming every four years.
But Orthodox Churches did not adopt Gregory’s reform, and so while they also use March 21 as their ecclesiastical vernal equinox, their March 21 falls, these days, on April 3 of the Roman calendar.
Pretty straightforward, huh?
At any rate, the Orthodox also have a rule that Easter must fall after Passover, while the Catholic Church does not, so in years when Passover would fall before Easter otherwise, the Orthodox wait until the Sunday after the second full moon after the vernal equinox.
All those complications mean that there is a scenario in which the Orthodox and Catholic Easters can fall on the same date.
How? Well, if the first full moon after the equinox falls after April 3 on the Gregorian calendar — thus putting it after the Orthodox calculation of the vernal equinox — and if Passover has already occurred before the date which the Catholic Church would calculate for Easter, then Catholic and Orthodox Easter align.
That actually happens about a quarter of the time, and will mean a unified Christian Easter in 24 of the next 100 years. As it happens, 2025 is one of those lucky years, and so Catholic and Orthodox believers will celebrate Easter together on April 20.
The next time that will happen is in 2028, when both Churches will celebrate Easter on April 16th.
Pope Francis has often expressed a desire to reach a unified method of calculating Easter with Orthodox Christians.
Over the centuries, others have suggested making Easter a fixed-date solemnity like Christmas. That proposal seems unlikely — and fixing the date would separate the connection of Christ’s death and resurrection from the movement of our own planet, moon, and sun through the heavens.
Plus, if the date were fixed, people would never have the chance to talk about how late — or early — Easter is coming that year.
