count the number of unique values given certain conditions

Thanks for the replies!

FDibbins, a pivot table won't help me. if you want to see who called which numbers, you'll have to expand the data range to include column A through D then drag the Name field to the row labels and finally filter by august and outbound.

Haseeb A and vlady, i tried both of your formulas and i'm getting some errors.

SUM(IF(FREQUENCY(IF($A$2:$A$100="Angela",IF($B$2:$B$100="August",IF($C$2:$C$100="Outbound",MATCH("~"&$D$2:$D$100,$D$2:$D$100&"",0)))),ROW($D$2:$D$100)-ROW(D2)+1),1)) this returns an error, #value!

SUM(IF(FREQUENCY(IF((A$2:A$61="Angela")*(B$2:B$61="August")*(C$2:C$61="Outbound"),D$2:D$61),D$2:D$61),1)) the results is 12 and that's the count of unique phone numbers in the whole data set regardless of the criteria. also, the formula seems to be dependent on how the data is sorted. if i'm using the formula for angela and angela is listed first, then it'll return 12, but if not then it returns the error, #value!. i can't have the data dependent on how its sorted.