detect duplicate number in a column

**rossryan** · 10-05-2009, 11:12 PM

I have data in “sequence no” that represent id number data entered to this cell should be unique. How would I know if I have a duplicate entry? Is there a way a program or scripts in excel that would let know I have a duplicate number in a column?

I have attached the sample file.

thanks in advance.

**DonkeyOte** · 10-06-2009, 02:54 AM

The file uploaded is 2007 format (profile indicates 2003) -- in 2007

If you wish to format them...
-- you can format the Dupes using Conditional Formatting (Home section on Ribbon) - Highlight Cells Rules - Duplicate Values (set format accordingly)

If you wish to delete them...
-- you have Remove Duplicates option in Data tab on Ribbon

If you want to populate Column B per your sample

B2: =REPT("DUPLICATE",COUNTIF(A:A,$A2)>1)
copied down