DAYS in Collabora Office Calc: Measure Signed Date and Time Differences

• Introduced: original Collabora release and launch date are not established by the sources reviewed.
• Availability: documented in Collabora Office 26.04 help, scoped to that desktop-help release.
• Platform scope: separately deployed Online and mobile versions are not inferred from desktop documentation.
• Checked: October 14, 2026. Direct documentation and independent calendar/time controls; no native Collabora test was performed.

=DAYS(end_date;start_date)

Both dates are required. If the end is earlier than the start, the documented result is negative. The result is a number of days, so display it as a number rather than formatting it as a date.

Use DATE expressions or verified date cells for these controls. Unquoted slashes or dashes inside a formula are arithmetic operators, not an unambiguous date literal.

=DAYS(DATE(2026;10;14);DATE(2026;10;1))
=DAYS(DATE(2026;10;1);DATE(2026;10;14))
=DAYS(DATE(2026;10;14);DATE(2026;10;14))

Expected numeric results are 13, −13 and 0. Reversing the argument order reverses the sign, while identical date values have no elapsed difference.

The forward result 13 does not count both endpoint labels inclusively. If a separate reporting policy counts calendar dates October 1 through October 14, there are 14 labels; adding one expresses that particular inclusive policy for an ordered, date-only interval.

=DAYS(DATE(2024;3;1);DATE(2024;2;28))
=DAYS(DATE(2026;3;1);DATE(2026;2;28))

Expected differences are 2 and 1 days. February 29 lies between the first pair of dates, while 2026 has no leap day.

For a full modern calendar year, =DAYS(DATE(2025;1;1);DATE(2024;1;1)) has expected result 366. Calendar arithmetic should not assume 365 days for every year.

Create start and end values as follows:

=DATE(2026;10;14)+TIME(9;30;0)
=DATE(2026;10;15)+TIME(12;0;0)

Place them in A2 and B2, respectively. Then calculate:

=DAYS(B2;A2)
=DAYS(B2;A2)*24

Expected results are 1.104166667 days, approximately, and 26.5 hours. The elapsed interval is one full day plus two and a half hours. Collabora’s direct DAYS documentation supports retaining this fractional part.

Do not replace that result with an assumed integer just because another spreadsheet’s identically named function follows a different rule. The displayed decimal is a rounded expectation; keep the underlying result for later calculations.

For those same timestamps, reconstruct date-only values:

=DAYS(DATE(YEAR(B2);MONTH(B2);DAY(B2));DATE(YEAR(A2);MONTH(A2);DAY(A2)))

Expected result: 1 day. This deliberately discards both time fractions and measures the difference between the calendar dates.

The result differs from 26.5 elapsed hours because the question changed. Neither calculation performs timezone conversion. The official date/time guide states that timezone information is not used in these cell values.

Let A2 be 14 October 2026 at 09:30, B2 be 15 October 2026 at 12:00, and C2 be 16 October 2026 at 09:30, each constructed with DATE plus TIME.

The differences are 26.5 hours from A2 to B2 and 21.5 hours from B2 to C2. Their sum is 48 hours, matching the direct A2-to-C2 interval of two days.

This is a consistency check on numeric date/time subtraction. It does not imply that subtracting local clock labels across a daylight-saving change measures real elapsed time without additional timezone information.

DAYS counts ordinary elapsed calendar time. It does not exclude weekends or a holiday list. NETWORKDAYS addresses a different work-calendar question with its own arguments.

The source’s TODAY example contains an extra closing parenthesis; the formulas here are independently balanced, fixed-date controls. No volatile current-date result is claimed. Exact malformed-text errors, alternate date-base imports and extreme historical-date behavior remain outside this review.

• Collabora Office 26.04: DAYS.
• Collabora date/time model and date bases.
• Editorial testing standards.

The dedicated product help was read directly. Calendar and numeric outputs are independently calculated expectations, with stated parsing and boundary limits. No native runtime or universal cross-deployment certification is claimed.