Assuming your data in A1:B7

In C1: =IF(SUMPRODUCT(($A$1:$A$7=A1)*($B$1:$B$7=B1))1,"D up","")
copy down to C7


"Louja" wrote:

How do I write a formula that looks at two columns and looks for
duplicate values in both, and flags the row if it finds them in?

See below example I would want to look at columns A and B and look for
duplicate values in both columns

A B
123 abc
124 def
125 ghi
126 jkl
126 mno
126 mno
127 pqr
.