Find duplicate numbers in large Excel Spreadsheet

[Table]

[rae820]

if you are working in a list...you can have a separate column that will display the text "Duplicate" if the numbers are in fact duplicated...

=IF(COUNTIF($A$1:A1,A1)>1 "DUPLICATE", "Unique")

A= the column you would like to check 1= the row you would like to start checking

the function would go in a column to the side and then you can sort the data by duplicate numbers and delete those rows!