EASTERSUNDAY Function (OpenOffice Calc)

• Introduced: First release not established; documented by OpenOffice.org 3.3.
• Supported in: Apache OpenOffice 4.1.16; this is a verified release, not a final supported version.
• Scope: Desktop Calc, English function names and semicolon-separated formulas.
• Checked: October 14, 2026. Eight ordinary reference formulas were recalculated from generated ODF in 4.1.16 on Linux x86-64, Build 9816. Source and independent calendar arithmetic were checked.

EASTERSUNDAY returns the date of Easter Sunday calculated with the Gregorian computus used in the pinned implementation. Unlike the other one-argument date functions in this group, its argument is a year number, not a date serial. Release implementation.

EASTERSUNDAY(Year)

• Year: one required four-digit year number for an unambiguous call, such as 2026.
• The interpreter floors the numeric input before converting it to its year type. Values below 100 pass through the application’s two-digit-year expansion setting. Use four digits instead of relying on that setting; those ambiguous inputs were not tested.

The native serials are also interpreted as Gregorian calendar dates under the workbook’s 1899-12-30 date epoch. Numerical values are shown to twelve decimal places where needed. Enter the DATE expressions directly rather than substituting locale-dependent text.

=EASTERSUNDAY(2026) returns the serial for April 5, 2026. Set the result cell’s format to a date to display the calendar value. The equivalent 2025 result is April 20, and the 2024 result is March 31.

For a date two days before the returned Sunday, use =EASTERSUNDAY(A2)-2 with a year in A2. For 2026 this produces April 3. Adding one gives April 6. These are arithmetic offsets from the calculated date; whether they are holidays in a particular jurisdiction requires separate information.

The Gregorian calculation combines the year’s position in the 19-year lunar cycle with century corrections and weekday arithmetic. Its result lies between March 22 and April 25. The eight selected years include both 1900 and 2000, so century corrections are represented rather than assumed.

An independent weekday check confirms that every listed result is Sunday. Do not replace this rule with a fixed number of days after March 21 or a repeating 19-year lookup: Gregorian century corrections mean that shortcut is not generally valid.

This is the Gregorian Easter calculation, not a universal date for every church’s Easter observance and not a historical civil-calendar conversion. The 1900 result describes this computus; it does not establish which calendar a particular country used.

Use a four-digit year in a normal calendar range. Negative, very large and two-digit years were not executed. The source uses a bounded integer year type, so an unqualified “any integer year” promise would be misleading. The test consists of generated ODF formulas and saved date results, not manual entry.

DATE, YEAR, WEEKDAY.

• Function-specific release implementation

The generated ODF produced the informational load warning “Not all attributes could be read.” The sheet was hard-recalculated and saved separately. All eight ordinary function identities and results were reconciled; a stale SUM cache changed from 999999 to 3 and an uncached SUM returned 7. This establishes the stated examples, not every workbook style or invalid input. Other explanatory identities are independent calculations. The authoring-tool XLSX was not executed in OpenOffice, and its preview values are not the native results reported here.