LibreOffice 25.2 Help
Adds a date or time interval to a given date a number of times and returns the resulting date.
DateAdd (interval As String, number As Long, date As Date) As Date
A Variant containing a date.
interval - A string expression from the following table, specifying the date or time interval.
| interval (string value) | Explanation | 
|---|---|
| yyyy | Year | 
| q | Quarter | 
| m | Month | 
| y | Day of year | 
| w | Weekday | 
| ww | Week of year | 
| d | Day | 
| h | Hour | 
| n | Minute | 
| s | Second | 
number - A numerical expression specifying how many times the interval value will be added when positive or subtracted when negative.
date - A given date or the name of a Variant variable containing a date. The interval value will be added number times to this date.
Sub example_dateadd
    MsgBox DateAdd("m", 1, #1/31/2004#) &" - "& DateAdd(date:=#2005-01-31#, interval:="m", number:=1)
End Sub