DAY
Quirk foundCategory: Date and time · Last tested 2026-07-04
Support matrix
| Engine | Documented | Live-tested | Verdict |
|---|---|---|---|
| Excel | Yes | Not yet | n/a |
| Google Sheets | Yes | Not yet | n/a |
| LibreOffice Calc | Yes | Yes (24.2.7.2, 2026-07-04) | Quirk found |
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 24.2.7.2 (tested 2026-07-04)
| 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