I have two columns of data in Excel 2010. One column has about 5,000 cells and the other has usually has 20-30. I need to be able to compare the two columns and output to a third if there is a duplicate. Any ideas?
The fastest way is to use conditional formatting and highlight the duplicates:
Click on the Home tab.
Click on the Conditional Formatting icon on the ribbon to open the drop down menu.
Choose Highlight Cell Rules > Duplicates Values... to open the conditional formatting dialog box.
Select Light Red Fill with Dark Red Text from the list.
Click OK to accept the selections and close the dialog box.