DAY

Quirk found

Category: Date and time · Last tested 2026-08-06

Real, executed compatibility results for the DAY function across Microsoft Excel, Google Sheets, and LibreOffice Calc — verified by actually running it. Syntax and links to each vendor’s official documentation are below.

Support matrix

Engine	Documented	Live-tested	Verdict
Excel	Yes	Not yet	n/a
Google Sheets	Yes	Not yet	n/a
LibreOffice Calc	Yes	Yes (25.8.7.3, 2026-08-06)	Quirk found

LibreOffice version history

We executed the same test cases under each LibreOffice release to show exactly when DAY’s support changed — not documentation claims, real results.

LibreOffice version	Verdict	Tested
24.2.0.3	Quirk found	2026-07-19
24.8.7.2	Quirk found	2026-07-19
25.2.0.3	Quirk found	2026-07-24
25.8.7.3	Quirk found	2026-08-06

Why isn't DAY working in LibreOffice?

DAY exists in LibreOffice 25.8.7.3, but it is not a drop-in match for Excel — our executed tests found real behavioral differences (detailed in the test results on this page). If a formula that works in Excel or Google Sheets misbehaves in LibreOffice, compare your usage against the failing cases above before assuming your data is wrong.

Discovered quirks

=DAY(1) on LibreOffice Calc returned 31, but the documented/expected result is 1. Serial 1 is Jan 1, 1900 in the 1900 date system; MISMATCH vs expected: expected 1, got 31

Executed test cases

LibreOffice Calc 25.8.7.3 (tested 2026-08-06)

Formula	Description	Result	Expected	Verdict
=DAY(DATE(2024,3,15))	DAY applied to a constructed date	15	15	Matched
=DAY(1)	DAY applied directly to the raw serial number 1 (Jan 1, 1900)	31	1 Serial 1 is Jan 1, 1900 in the 1900 date system	Mismatch
=DAY(45366.75)	A serial with a fractional (time-of-day) component still resolves to the correct calendar day	15	15 45366 = 2024-03-15; the .75 fractional day is ignored by DAY	Matched

Docs & syntax

Excel: official documentation
Google Sheets: official documentation
LibreOffice Calc: official documentation

DAY