I'm sure you've asked this before. Just subtract the start date from
the end date and it will give you the number of days (format the cell
as general). If you want to exclude the dates then subtract 1, if the
dates are inclusive then add 1, i.e.:
=B1-A1-1 (exclude dates)
or
=B1-A1+1 (inclusive dates)
Hope this helps.
Pete