Counting the number of unique values
For example, you want to count the number of unique values of the range:
You can enter the next formula to the range C2:C12:
= SUM (1 / COUNTIF ($A$2:$A$12, $A$2:$A$12))
Summarize amount from a range C2:C12:
This formula in Excel 2016 has no limitation: If the range contains any blank cells, previous versions of Excel return an error.
See also this tip in French: Compter le nombre de valeurs uniques.