Easter Calculator

Instantly compute the date of Western Easter Sunday using the precise Gregorian Computus. Enter a year to unlock Holy Week milestones, neighboring Easter dates, and planning insights.

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Enter a year to reveal Easter Sunday and the key observances around it.

How Easter Sunday Is Calculated

Western churches determine Easter Sunday with the Gregorian Computus, the method standardized by Pope Gregory XIII in 1582 and outlined in modern references such as the U.S. Naval Observatory and the Meeus/Jones/Butcher algorithm. The calculation tracks a 19-year Metonic cycle to approximate the Paschal full moon, then anchors Easter to the first Sunday after that moon on or after March 21, the ecclesiastical spring equinox.

The algorithm works through a sequence of modular arithmetic steps: identifying the year’s position in the Metonic cycle, adjusting for Gregorian leap-year corrections, locating the Paschal full moon, and finally advancing to the following Sunday. This approach faithfully reproduces the ecclesiastical tables used by Western Christianity, keeping Easter between March 22 and April 25.

Key Computus Milestones

• Metonic cycle: Repeats lunar phases every 19 years, driving the “Golden Number.”
• Century corrections: Adjust leap years to keep the solar calendar aligned.
• Epact calculation: Pinpoints the ecclesiastical full moon date.
• Sunday offset: Ensures Easter always lands on a Sunday following the Paschal full moon.

Holy Week Timeline At a Glance

Once you know the Easter date, you can map the rest of the season. Churches, schools, and families use these markers to plan services, breaks, and travel.

Lead-Up Observances

• Ash Wednesday begins Lent 46 days prior.
• Palm Sunday marks Jesus’ entry one week before.
• Maundy Thursday focuses on the Last Supper.
• Good Friday remembers the crucifixion.

Eastertide Highlights

• Easter Monday follows as a civil observance in many countries.
• Ascension Day falls 39 days afterward.
• Pentecost closes the 50-day Easter season.

Planning Tip

Many schools schedule spring break to align with Holy Week, so booking travel early can help avoid price surges. Use the neighboring-year table above to plan for multiple years at once.

Liturgical Insight

Western and Eastern churches sometimes celebrate on different Sundays because Eastern Orthodoxy still bases its Computus on the Julian calendar. This tool focuses on the Gregorian method used by Roman Catholic, Protestant, and many Anglican traditions.

Ways to Use the Easter Calculator

From church staff to community event planners, accurate Easter dates keep everyone on the same page. Here are a few popular ways people use this tool.

Service Scheduling

Map rehearsal nights, sunrise services, and vigil liturgies with confidence by anchoring them to verified Holy Week dates.

Family Travel

Coordinate visits and vacations around school breaks and long weekends tied to Easter Sunday and Easter Monday.

Historical Projects

Historians and genealogists use Computus-based calculators to date diaries, letters, and archival church records with seasonal references.

Frequently Asked Questions

What years does this Easter calculator support?

The calculator covers Gregorian years from 1583 through 4099, matching the range recommended by astronomical tables published by institutions such as the U.S. Naval Observatory. Earlier dates require the Julian calendar, while far-future dates may need updated leap-year corrections.

Why can Easter fall anywhere between late March and late April?

Easter is linked to the Paschal full moon rather than a fixed solar date. Depending on how the lunar cycle aligns with the ecclesiastical equinox, Easter can shift across a five-week span—from March 22 to April 25.

How does this differ from Orthodox Easter calculations?

Orthodox churches use the Julian calendar and apply additional rules about Passover timing, so their Easter can be one to five weeks later. This calculator delivers the Western (Gregorian) observance used by Roman Catholic and most Protestant denominations.

Can I embed this calculator on my website?

Yes. Scroll to the embed section below to grab a ready-made iframe snippet. The embedded version uses the exact same Computus logic as the on-page calculator for consistent results.

How reliable is the Computus algorithm today?

The Meeus/Jones/Butcher implementation matches the official Gregorian tables for all supported years. It is the same formula reproduced by the U.S. Naval Observatory and other reputable astronomical sources, ensuring accuracy for modern planning.

Embed Easter Calculator

Add our Easter calculator to your website or blog. Deliver accurate Western Easter Sunday dates, Holy Week milestones, and neighboring-year context with a single embed.