Find the unique values in a range

This formula returns the number of unique items in a worksheet range "=SUM(1/COUNTIF(Rge,Rge))
This will only work if the range does not contain blank cells
If it does you can use: "=SUM(COUNTIF(RgemRge)/IF(NOT(COUNTIF(rge,Rge)),1,COUNTIF(Rge,Rge))^2).