Add and count
Mark which rows are duplicates
=IF(COUNTIF($A$2:$A$6,A2)>1,"Duplicate","Unique")How it works in Excel
- COUNTIF counts how often this row's value appears.
- More than once means it is a duplicate.
- Copy it down beside your list.
- To color them instead, use Conditional Formatting, then Highlight Cells Rules, then Duplicate Values.
The idea in general
Count how often each name appears, and anything above one is a repeat.
What I assumed
- Your list is in A2:A6.
Check the result on your own data before relying on it.