Easter 2026 falls on Sunday, April 5, but the date changes every year—a fact that leaves many wondering how the holiday's timing is determined. Unlike fixed holidays like Christmas, Easter is a "movable feast" that dances across the calendar based on ancient lunar calculations and ecclesiastical rules established nearly 1,700 years ago. Understanding why Easter shifts requires diving into the intersection of astronomy, church history, and mathematical algorithms that have been refined over centuries.
How Easter's Date is Determined: The Lunar Connection
The formula for Easter is deceptively simple: it falls on the first Sunday after the first full moon that occurs on or after the spring equinox. However, both the equinox and the full moon used in this calculation are not the actual astronomical events but fixed ecclesiastical dates designed to create a predictable calendar. The Church sets the equinox at March 21 regardless of the astronomical equinox, which can vary between March 19 and 22. Similarly, the "Paschal Full Moon" is determined using a 19‑year lunar cycle called the Metonic cycle, which approximates but doesn't always match the actual full moon.
This system ensures that Easter always falls between March 22 and April 25 in the Gregorian calendar. If the Paschal Full Moon itself lands on a Sunday, Easter is celebrated the following Sunday. The method was standardized by the Council of Nicaea in 325 CE to unify Christian observance across the Roman Empire, though refinements continued for centuries.
From Nicaea to Gregorian Reform: The History of Easter Calculation
The quest to pin down Easter’s date began long before the Council of Nicaea. Early Christians debated whether to celebrate Easter on the same day as Passover or on the following Sunday. The Council’s decision to link Easter to the spring equinox and the full moon created the computus—the mathematical procedure for calculating the date. In the 6th century, Dionysius Exiguus created widely used Easter tables, and by the 8th century, the Venerable Bede wrote extensively on computus in his work "The Reckoning of Time."
The next major shift came in 1582 with the Gregorian calendar reform. Pope Gregory XIII’s commission, led by Christopher Clavius, revised the Easter tables to account for inaccuracies that had crept into the Julian calendar. The Gregorian calendar’s improved leap‑year rule brought the ecclesiastical equinox closer to the astronomical equinox and produced the Easter calculation still used by most Western churches today. Eastern Orthodox churches, however, continued using the older Julian calendar, leading to the frequent discrepancy between Western and Orthodox Easter dates.
Why Easter Changes and How Often Dates Repeat
Because Easter is tied to lunar cycles, its date shifts each year relative to the solar‑based Gregorian calendar. Lunar months are about 29.5 days long, so the Paschal Full Moon can occur up to a month earlier or later than the previous year. Over a 500‑year period (1600–2099), the most common Easter dates are March 31 and April 16, each appearing about 5% of the time. The rarest date is March 22, which occurs only a handful of times per millennium.
The difference between Western and Orthodox Easter arises from the calendar divide. Orthodox churches follow the Julian calendar, which currently lags 13 days behind the Gregorian calendar. Additionally, some Orthodox churches still use the older Julian equinox date (April 3 on the Gregorian calendar) and different lunar tables. Consequently, Orthodox Easter can fall anywhere from April 3 to May 10 on the Gregorian calendar, and it coincides with Western Easter only when the full‑moon and Sunday conditions align across both systems—as they will in 2028.
Easter 2026 and the Lenten Calendar
For 2026, Western Easter Sunday is April 5. This date sets the entire Lenten season in motion: Ash Wednesday—the start of Lent—falls 46 days earlier on February 18. Good Friday is observed on April 3, and Easter Monday follows on April 6. In Orthodox traditions, Easter 2026 will be celebrated on April 12, a week later than the Western date.
The 2026 Easter weekend also aligns with other spring holidays and school breaks, making it a popular time for travel and family gatherings. Knowing the exact date helps churches, schools, and businesses plan well in advance.
Future Easter Dates and Proposed Reforms
Looking ahead, Easter will continue to move within its March‑22‑to‑April‑25 window. In 2027, Western Easter falls on March 28; in 2028, both Western and Orthodox Easter coincide on April 16. Over the next decade, Easter will occur in early April more often than in late March.
There have been repeated efforts to fix Easter to a specific calendar date. In 1928, the United Kingdom passed the Easter Act to set Easter as the first Sunday after the second Saturday in April, but the law was never implemented. More recently, the World Council of Churches proposed in 1997 to calculate Easter using actual astronomical observations rather than tables, which would harmonize dates across Christian denominations. However, no reform has gained universal acceptance, and the movable feast remains a unique feature of the Christian calendar.
The Bottom Line: Key Points to Remember
- Easter 2026: Sunday, April 5 for Western churches; April 12 for Orthodox churches.
- How it's calculated: First Sunday after the Paschal Full Moon following the ecclesiastical equinox (fixed on March 21).
- Date range: March 22 to April 25 (Gregorian calendar).
- Why it changes: Easter follows lunar cycles, which don't align perfectly with the solar year.
- Historical roots: The formula was set by the Council of Nicaea (325 CE) and refined with the Gregorian calendar (1582).
- Most common dates: March 31 and April 16 over a 500‑year period.
