Highlight cells that are duplicate pairs

[erob223]

Hi, I'm trying to get Excel 2010 to highlight duplicate matching pairs in two columns. See attached. Basically, I have column A with a box number and column B with a lot number. Any duplicates of the same box number paired with the same lot number need to be highlighted, but the same lot number can be paired with a different box number and vice versa. I've tried using this formula =SUMPRODUCT((CONCATENATE($A$6:$A$100,"^",$B$6:$B$100)=CONCATENATE(B6,"^",A6))*1)>0 but I can't seem to get it to work correctly. Thanks for any help!

[samba_ravi]

=COUNTIFS($A:$A,$A6,$B:$B,$B6)>1
Try this in conditional format formula

[erob223]

Thank you! That worked perfectly!

[samba_ravi]

you are welcome