Date & Time Functions

These spreadsheet functions are used for inserting and editing dates and times.

To access this command...

Insert - Function - Category Date & Time

The functions whose names end with -ADD or -EXCEL2003 return the same results as the corresponding Microsoft Excel 2003 functions without the suffix. Use the functions without suffix to get results based on international standards.

Office internally handles a date/time value as a numeric value. If you assign the numbering format "Number" to a date or time value, it is converted to a number. For example, 01/01/2000 12:00 PM, converts to 36526.5. The value preceding the decimal point corresponds to the date; the value following the decimal point corresponds to the time. If you do not want to see this type of numerical date or time representation, change the number format (date or time) accordingly. To do this, select the cell containing the date or time value, call its context menu and select Format Cells. The Numbers tab page contains the functions for defining the number format.

Date base for day zero

Dates are calculated as offsets from a starting day zero. You can set the day zero to be one of the following:

Date base	Use
'30/12/1899'	(default)
'01/01/1900'	(used in former StarCalc 1.0)
'01/01/1904'	(used in Apple software)

Choose Tools - Options - Office Calc - Calculate to select the date base.

When you copy and paste cells containing date values between different spreadsheets, both spreadsheet documents must be set to the same date base. If date bases differ, the displayed date values will change!

Two digits years

In Tools - Options - Office - General you find the area Year (two digits). This sets the period for which two-digit information applies. Note that changes made here have an effect on some of the following functions.

When entering dates as part of formulas, slashes or dashes used as date separators are interpreted as arithmetic operators. Therefore, dates entered in this format are not recognised as dates and result in erroneous calculations. To keep dates from being interpreted as parts of formulas use the DATE function, for example, DATE(1954;7;20), or place the date in quotation marks and use the ISO 8601 notation, for example, "1954-07-20". Avoid using locale dependent date formats such as "07/20/54", the calculation may produce errors if the document is loaded under different locale settings.

Unambiguous conversion is possible for ISO 8601 dates and times in their extended formats with separators. If a #VALUE! error occurs, then unselect Generate #VALUE! error in Tools - Options - Office Calc - Formula, button Details... in section "Detailed Calculation Settings", Conversion from text to number list box.