Where are your holidays defined? There are about 100 holidays on my desk
calendar. Does your Access application know which ones are valid?
Have you done a search for this? There are several samples out there to
help you build in this feature. It is not nearly as simple as your question
implies.
You would need a table listing all holidays...then query for holidays
between a given set of dates. Then subtract the number of holidays found
from the elapsed number of days.