dateDiff(interval, dateFrom, dateTo) calculates the number of intervals (for example: "d" = days) between dateFrom and dateTo.
option explicit
sub main() ' {
dim dtStart as date
dim dtEnd as date
dtStart = dateSerial(2018, 8, 18)
dtEnd = dateSerial(2018, 8, 28)
dim daysBetween as long
daysBetween = dateDiff("d", dtStart, dtEnd)
debug.print("There are " & daysBetween & " days between " & dtStart & " and " & dtEnd)
'
' There are 10 days between 18.08.2018 and 28.08.2018
'
end sub ' }