Counting Values that Appear Only Once in

[ExcelTip]

Problem:

Counting the number of values in List1 (column A) that appear only once within the list.

Solution:

Use the SUM, IF, and COUNTIF functions as shown in the following Array formula:
{=SUM(IF(COUNTIF(A2:A7,A2:A7&\"\")=1,1,0))}