I'm using the following formula to create a total of unique values
=SUM(IF(FREQUENCY(MATCH(C4:C9,C4:C9,0),MATCH(C4:C9,C4:C9,0))>0,1))
However, I'm now using an autofilter, so I now need it to sum only the visible rows. I've read that I need to use SUBTOTAL instead of SUM, but I'm not sure how to change the formula above correcly.
Any ideas?