Find the smallest or largest duplicate
This rule is unstable if you use normal referencing, so apply a range name to your data set before applying the conditional formatting rule. The rule shown here will highlight the value 3 in the range named List only if 3 is also a duplicate. (To find the largest duplicate value, substitute the MIN() function with MAX().)
Susan Sales Harkins is an IT consultant, specializing in desktop solutions. Previously, she was editor in chief for The Cobb Group, the world's largest publisher of technical journals.