Hi Itsbarbara,
the solution you found thanks to Bob's suggestion is perfect. The use of helper columns is advocated by many MVP's.
The drawback might be that using VLOOKUP on very large tables slows things down but I don't expect there will be 65000 employees/time combinations or more, or several hundred dates.
An alternative , without a helper column is
Code:
=SUMPRODUCT(([Check_IN.xls]EmployeeData!$A$3:$A$1257=$A2)*([Check_IN.xls]EmployeeData!$C$3:$C$1257=B$1)*[Check_IN.xls]EmployeeData!$D$3:$D$1257)
I suspect it won't be any faster, but in any case, it will give Bob something to chew on

.
FWIW in your EmployeeData table you can enter =C3 in B3, pull down and custom format as dddd. So you don't have to type the days
@ Bob BTW thanks for the advertising, but I'm far from being good at Excel