Array formulas are pretty handy. This example looks for records that match columns A, B & C between 2 sheets, returns the text “Duplicate” only if there is a record that matches all 3 columns and nothing if it doesn’t… There aren’t many Excel instructors who teach Excel to this level – but I do. Book an Expert Excel class to get your head around arrays. Danielle O'Connell's answer to How can I identify duplicates between two Excel sheets? on Quora