If you want to put the file name into a cell, then use:

=MID(CELL("filename",Z100),FIND("[",CELL("filename",Z100),1)+1,FIND("]",CELL("filename",Z100),1)-FIND("[",CELL("filename",Z100),1)-1)

will return something like:

Book1.xls

=MID(CELL("filename",Z100),FIND("[",CELL("filename",Z100),1)+1,FIND("]",CELL("filename",Z100),1)-FIND("[",CELL("filename",Z100),1)-5)

will return

Book1
--
Gary''s Student


"jack_mel" wrote:

I am using excel for invoices & billing. The file name is the same as the
invoice number. how do I format a cell to do this automatically? Is there a
formula for this? and also, I also need to calculate time: say start time is
8:00am - finish time is 11:15am, is there a formula to caculate 3.25 hours?
any help will be greatly appreciated!