Hello Nee,
Here are a couple of ideas to choose from.
1) jm14's conditional formatting suggestion.
Highlight the entire range or column.
Conditional Format with formula being: =COUNTIF(A:A,A1)>1 and format
to suit.
2) A formula to show the row a duplicate occurs in. (Needs to go into a separate
column and copy down.)
=IF(COUNTIF(A:A,A1)>1,ROW(INDEX(A:A,MATCH(A1,A:A,0),1)),"")
3) A formula to show the number of times a duplicate is repeated. (Needs to go into a separate
column and copy down.)
=IF(COUNTIF(A:A,A1)<2,"",COUNTIF(A:A,A1))
One or the other of these ought to get you what you need.