Count of duplicates in a column

[Danger_SF]

Good morning!

Is there a formula that can be used to give me a count of duplicate values in a column? 

To be clear, I'm not trying to count known duplicate values that I can include in a COUNTIF formula, such as =COUNTIF(A:A),"Specific Text". I'm looking for Excel to simply count how many times it sees a duplicate of any kind. See attached.

[#2 · Accepted solution]

@Danger_SF 

If you want the number of unique entries:

=COUNTA(UNIQUE(D3:D12))

If you want the number of entries that occur more than once:

=SUM(--(COUNTIF(D3:D12,UNIQUE(D3:D12))>1))

[#3]

Thank you for your help.