I work for a temporary housing company and would like to create a calendar
where all i have to do is put the clients name and dates they are staying in
a "key" and it will automatically block out that range of date an a calendar
(and preferrable tent the cell red meaning occupied). Does anyone have any
advice on what formula would get this accomplished?

Thank you in advance!!

Suggest vlookup formula in conditional formatting.
Requires the date to be in the cell of the calendar date.
vlookup on cell date to see if it is in the key.
For exmaple if the date within the key is in C1 to C8 then the vlookup
within conditional formatting in cell A1 is:
=VLOOKUP(A1,$C$1:$C$8,1,FALSE)

Ando
Click yes if it helped