1. What is Easter Day Calculation?

The calculation of Easter determines the date of Easter Sunday in the Gregorian calendar. It's based on a computus (calculation) that takes into account lunar cycles and the March equinox.

2. How Does the Calculator Work?

The calculator uses the Gauss algorithm for Easter calculation:

Where:

• \( e \) — Calculated from year's position in the 19-year lunar cycle and other factors
• \( f \) — Correction factor based on calendar cycles
• The result gives either a March date (if ≤ 31) or April date (if > 31)

Explanation: The algorithm accounts for the complex relationship between the solar year and lunar month that determines Easter's date.

3. Importance of Easter Calculation

Details: Accurate Easter calculation is crucial for Christian liturgical calendars, as many other movable feasts are calculated relative to Easter. It also affects secular calendars for holidays and school breaks.

4. Using the Calculator

Tips: Enter any year between 1583 (when the Gregorian calendar was introduced) and 9999. The calculator will determine the date of Easter Sunday for that year.

5. Frequently Asked Questions (FAQ)

Q1: Why does Easter's date change every year?
A: Easter is calculated to fall on the Sunday following the first full moon after the March equinox, which follows lunar cycles.

Q2: What's the earliest possible date for Easter?
A: March 22 (last occurred in 1818, will next occur in 2285).

Q3: What's the latest possible date for Easter?
A: April 25 (last occurred in 1943, will next occur in 2038).

Q4: Does this work for Orthodox Easter?
A: No, Orthodox churches use the Julian calendar for Easter calculation, resulting in different dates most years.

Q5: Why does the algorithm get complicated?
A: It reconciles three different cycles: the solar year (365.2422 days), the lunar month (29.53059 days), and the week (7 days).