Conditional Formatting To Red out a Row, if ID# has been used before

Mathew Palter

Hi all,

I am trying to create a conditional formatting to mark a row Red if the ID# has been used before. I have plenty of conditional formatting experience however I just can't seem to figure this part out. Basically in a list of projects I.e 1,2,3,4,5 they move at different speeds and sometimes a project wont be on a newer sheet so numbering can get confusing. If a 2nd project were to be added as project 4, I would want both to go red so I know to update 1 of them.

ker9

Hi @Mathew Palter

You may need a helper column to count duplicates and base your conditional formatting on that column.

=IF(COUNTIF([ID#]:[ID#], [ID#]@row) > 1, 1, 0)

Where the formula returns "1" there is a duplicate.

You could change it to use text if you prefer.

=IF(COUNTIF([ID#]:[ID#], [ID#]@row) > 1, "DUP", "OK")

Hope this helps!