Select the range of cells to check
Go to Home > Conditional Formatting > Highlight Cells Rules > Duplicate Values
Choose the formatting style and click OK
To find duplicates only, use Home > Conditional Formatting > Highlight Cells Rules > Duplicate Values, then set the rule to highlight duplicates
To remove duplicates: select the range > Data > Remove Duplicates > check the columns to consider > OK
To identify duplicates with a formula (mark duplicates): in a new column use
`=IF(COUNTIF($A$1:$A$100,A2)>1,”Duplicate”,”Unique”)`
To identify duplicates across multiple columns (mark duplicates): use
`=IF(COUNTIFS($A$1:$A$100,A2,$B$1:$B$100,B2)>1,”Duplicate”,”Unique”)`
To list only duplicate rows: filter the marked “Duplicate” column to show only “Duplicate”
To use a helper column for exact row duplicates: concatenate key fields then apply duplicate logic
`=A2&”|”&B2&”|”&C2`
then apply the duplicate highlighting or a `COUNTIF` on the helper column
To identify duplicates while ignoring blanks: use
`=IF(A2=””,””,IF(COUNTIF($A$1:$A$100,A2)>1,”Duplicate”,”Unique”))`