Go to D2 and enter the following formula:

=SUMPRODUCT(($A$2:$A$7=A2)*($B$2:$B$7=B2)*($C$2:$C $7=C2))

Now you have the auxiliary cells showing how many times each
combination appears. Assume now that week number is in G2 and machine
is in H2 .

=SUMPRODUCT((A2:A7=G2)*(B2:B7=H2)*(1/D2:D7))

HTH
Kostis Vezerides

On Dec 10, 2:21 pm, Lene S wrote:
Hi
I need Excel to count the unique appearances based upon two criterias.

The columns needed is:
Week Machine Order
40 1 A
40 1 B
40 1 A
40 2 C
41 1 D
41 1 A

How do I count the unique numbers of orders in week 40 and for machine 1? In
this case 2.

Thanks in advance
Lene S