Try...

=SUM(IF(FREQUENCY(IF(SUBTOTAL(3,OFFSET(Range,ROW(R ange)-MIN(ROW(Range)),,
1)),Range),IF(SUBTOTAL(3,OFFSET(Range,ROW(Range)-MIN(ROW(Range)),,1)),Ran
ge))0,1))

....confirmed with CONTROL+SHIFT+ENTER, not just ENTER.

Hope this helps!

In article ,
deb wrote:

Hi, I'm trying to use the formula =SUM(N(FREQUENCY(RANGE,RANGE)0)) to count
unique numbers which in the past has worked great, but now I'm using a
worksheet that is filtered and it's not working. Any suggestions?