Try
=SUMPRODUCT((A2:A10<"")/COUNTIF(A2:A10,A2:A10&""))

--
Jacob (MVP - Excel)


"Rechie" wrote:

Hi Expert, I need your help on how to count data but to ignore duplicates.

Below count results should be = 3 (ignore duplicates)
Inv No.
9123
9123
9125
9128
9128

Thanks for your support,