How to add hours (or minutes) to a time
✓ Verified in LibreOffice 25.8.7.3Shift a time forward — add a shift length, a processing delay, or a timezone offset.
The formula
| App | Formula | Notes |
|---|---|---|
| Excel | =A2+B2/24 | Hours divide by 24. Minutes: +B2/1440. Or add a real time value: =A2+TIME(B2,0,0). |
| Google Sheets | =A2+B2/24 | Identical. |
| LibreOffice Calc | =A2+B2/24 | Identical. |
How it works
Times are stored as fractions of a day, so an hour is 1/24 of the underlying number: 9:00 plus 5.5/24 lands at 14:30. Minutes use /1440 (24x60) and seconds /86400. The cleaner alternative is adding a genuine time value with TIME(hours,minutes,seconds), which reads better and avoids the mental division. If the sum crosses midnight the raw value rolls past 1.0 (a whole day) — format the cell as [h]:mm to show elapsed hours, or the date part increments if it's a full date-time.
Verified, not just documented
We ran =TEXT(TIME(9,0,0)+5.5/24,"H:MM") in LibreOffice 25.8.7.3 (headless, with forced recalculation) and it returned 14:30 — exactly the expected result. Every formula here is confirmed by actually executing it.