Counting duplicates in Excel

Question

I have a list of postcodes that includes duplicates. I would like to find out how many instances of each postcode there are.

For example I would like this:

Answer 1

If you perhaps also want to eliminate all of the duplicates and keep only a single one of each

Change the formula =COUNTIF(A:A,A2) to =COUNIF($A$2:A2,A2) and drag the formula down. Then autofilter for anything greater than 1 and you can delete them.