Find duplicates on two columns and across sheets

duplicates countifs cleanup

Flag rows that repeat on two columns, or that already appear on another sheet or list.

The problem

You need to catch repeats that depend on two columns, or values already on another sheet.

Formulas

Two columns: =COUNTIFS(A$2:A$5,""&A2,B$2:B$5,""&B2)>1   -> TRUE row 2, FALSE row 3
Across sheets: =COUNTIF(Sheet2!A2:A3,""&A3)>0           -> TRUE (A2 gives FALSE)

Simple one-column version on a name list: =COUNTIF($A$2:$A$6,A2)>1 gives TRUE for a name that appears twice. The $ signs lock the list so it does not slide when you fill down.

Excel vs Sheets

Same in both.

Tested on sample data by the Cellwise checker (logs CW-PL-20261018-40 and -44). AI-made: the text, voice and visuals are generated by AI.

Checked before publishing: a check.